Ch 18 : Wastewater Story

                                                                              Waste water  Story

1. Fill in the blanks:
(a) Cleaning of water is a process of removing ……………….

Answer: Contaminants

(b) Wastewater released by houses is called ……………

Answer: Sewage

(c) Dried ……………. is used as manure.

Answer: Sludge

(d) Drains get blocked by …………….. and …………………

Answer: Oil and fat

2. What is sewage? Explain why it is harmful to discharge untreated sewage into rivers or seas.

Answer: The liquid waste which has water as its largest component; along with various types of impurities; is called sewage. Discharging untreated sewage into rivers or seas contaminates the water of these water bodies. Contaminated water is dangerous for aquatic plants and animals. So, it is harmful to discharge untreated sewage into rivers or seas.

3. Why should oils and fats be not released in the drain? Explain.

Answer: Oil and fats can clog the drains. In open drains, they block the pores in the soil and thus hamper the filtration by soil. Hence, oil and fats should not be released in the drain.

4. Describe the steps involved in getting clarified water from wastewater.

Answer: The following steps are involved in clarifying wastewater:

• Insoluble waste is removed by filtration and sedimentation processes.

• Bacteria are allowed to grow through the process of aeration. Bacteria eat away human waste from the wastewater.

• Chlorination is used to kill the germs in clarified water. After this step, the water becomes fit even for human consumption.

5. What is sludge? Explain how it is treated.

Answer: The solid waste which settles at the bottom of the sedimentation tank is called sludge. The sludge is further treated by the process of aeration. This helps in growth of bacteria which eat away the human waste.

6. Untreated human excreta is a health hazard. Explain.

Answer: Untreated human excreta contains many microbes which can cause deadly diseases; like cholera, diarrhea, jaundice and typhoid. The germs of these diseases can easily reach human population through insects and through contaminated food and water. Thus, untreated human excreta are a health hazard.

7. Name two chemicals used to disinfect water.

Answer: Bleaching Powder and Chlorine Tablets

8. Explain the function of bar screens in a wastewater treatment plant.

Answer: Bar screens are large filters which are placed in the form of vertical screens. Large solid wastes; like sticks, pebbles, sand, cans, plastic bottles, plastic bags, etc. are filtered out when the wastewater moves through the bar screen.

9. Explain the relationship between sanitation and disease.

Answer: Sanitation and disease are closely related. Lack of sanitation leads to unhygienic conditions; which creates many communicable diseases. Maintenance of sanitation removes the chances of such diseases.

10. Outline your role as an active citizen in relation to sanitation.

Answer: My role as an active citizen can be in maintaining sanitation in the neighbourhood and at public places. For this, I shall follow these steps:

• Throwing garbage at designated places and in garbage bins.

• Preventing clogging of drains by not releasing oil and fat and solid waste into the drain.

• Using a dustbin to throw trash at public places.

• By not spitting at public places.

Ch 17 : Forest: Our Lifeline

                                    Forest: Our Lifeline

 

Question: 1 Explain how animals dwelling in the forest help it grow and regenerate.

Answer: Animals which live in the forest help it grow and regenerate in following ways:

(a) By eating vegetation they clear land for fresh growth

(b) Animals help flowering plants in pollination and seed dispersal

(c) Dead remains of animals make humus after decomposition. This increases soil fertility

Question: 2 - Explain how forests prevent floods.

Answer: Trees slow down the movement of running water and thus help in preventing floods.

Question: 3 - What are decomposers? Name any two of them. What do they do in the forest?

Answer: The organisms which decompose the dead remains of plants and animals are called decomposers. Fungi and bacteria are examples of decomposers. They clear the debris of dead remains and convert them into humus which enriches the topsoil.

Question: 4 - Explain the role of forest in maintaining the balance between oxygen and carbon dioxide in the atmosphere.

Answer: Green plants utilize carbon dioxide during photosynthesis and release oxygen in the process. Thus, the green plants maintain the balance of carbon dioxide and oxygen in the atmosphere.

Question: 4 - Explain why there is no waste in a forest.

Answer: Forest works like a self sustaining system. Whatever is produced in the forest is utilized by different components of the forest. Even the waste is converted into beneficial substances in a forest. Due to this, there is no waste in a forest.

Question: 5 - List five products we get from forests?

Answer: Following are the five products we get from forests:

Timber for furniture, firewood, lac, resin, honey

Question: 6 - Fill in the blank:
(a) The insects, butterflies, honeybees and birds help flowering plants in ………….

Answer: Pollination

(b) A forest is a purifier of ……………and ………………

Answer: Water and air

(c) Herbs form the ………………layer in the forest.

Answer: Understory

(d) The decaying leaves and animal droppings in a forest enrich the……………….

Answer: Topsoil

Question: 7 - Why should we worry about the conditions and issues related to forests far from us?

Answer: Forests affect the global environment in a great way. For example; reduced forest cover in a particular area leads to global warming which affects the whole earth. This is the reason we should worry about the conditions and issues related to forests which are even far from us.

Question: 8 - Explain why there is a need of variety of animals and plants in a forest.

Answer: Different animals and plants play different role in the system of a forest. For example; herbivores are needed to eat green plants and to provide food for the carnivores. Similarly, carnivores are needed to eat the herbivores and check their population. That is why there is a need of variety of animals and plants in a forest.

Question: 9 - Which of the following is not a forest product?
(i) Gum
(ii) Plywood
(iii) Sealing wax
(iv) Kerosene

Answer: (iv) Kerosene

Question: 10 - Which of the following statements is not correct?
(i) Forests protect the soil from erosion.
(ii) Plants and animals in a forest are not dependent on one another.
(iii) Forests influence the climate and water cycle.
(iv) Soil helps forests to grow and regenerate.

Answer: (ii) Plants and animals in a forest are not dependent on one another

 

Ch 16 : Water: A Precious Resource

                              Water: A Precious Resource

 

Question: 1 - Mark ‘T’ if the statement is true and ‘F’ if it is false:
(a) The freshwater stored in the ground is much more than that present in the rivers and lakes of the world. (T)
(b) Water shortage is a problem faced only by people living in rural areas. (F)
(c) Water from rivers is the only source for irrigation in the fields. (F)
(d) Rain is the ultimate source of water. (T)
Question: 2 - Explain how groundwater is recharged?

Answer: The surface water seeps down the ground through the porous layers of the soil. This process is called infiltration and is responsible for recharging the groundwater.

Question: 3 - There are ten tubewells in a lane of fifty houses. What could be the long term impact on the water table?

Answer: Ten tube-wells in a lane of fifty houses can lead people to mindlessly exploit the groundwater. This can lead to depletion of the water table in the long run.

Question: 4 - You have been asked to maintain a garden. How will you minimise the use of water?

Answer: Drip irrigation can be used in the garden to minimize the use of water.

Question: 5 - Explain the factors responsible for the depletion of water table.

Answer: Following factors are responsible for depletion of water table:

There is more demand of water due to increasing population. Increasing population means there is ever increasing demand of water for various human activities.

Deforestation has removed a large portion of forest cover. This has disturbed the natural process of recharging the groundwater.

While demand for water has increased, the supply has reduced. The mismatch between demand and supply is mainly responsible for depletion of water table.

Question: 6 - Fill in the blanks with the appropriate answers:
(a) People obtain groundwater through________ and ________.

Answer: Wells and tube-wells

(b) Three forms of water are ________, ________ and ________.

Answer: Ice, water and vapour

(c) The water bearing layer of the earth is ________.

Answer: Aquifer

(d) The process of water seepage into the ground is called ________.

Answer: Infiltration

Question: 7 - Which one of the following is not responsible for water shortage?
(i) Rapid growth of industries
(ii) Increasing population
(iii) Heavy rainfall
(iv) Mismanagement of water resources

Answer: (iii) Heavy rainfall

Question: 8 - Choose the correct option. The total water
(i) In the lakes and rivers of the world remains constant.
(ii) Under the ground remains constant.
(iii) In the seas and oceans of the world remains constant.
(iv) Of the world remains constant.

Answer: (iv) Of the world remains constant

 

Ch 15 : Light

                                                                                      Light

Question: 1 - Fill in the blanks:

1. An image that cannot be obtained on a screen is called ____________.
   
   Answer: Virtual
   
2. Image formed by a convex __________ is always virtual and smaller in size.
   
   Answer: Mirror
   
3. An image formed by a __________ mirror is always of the same size as that of the object.
   
   Answer: Plane
   
   
4. An image which can be obtained on a screen is called a _________ image.
   
   Answer: Real
   
   
5. An image formed by a concave ___________ cannot be obtained on a screen.
   
   Answer: Lens
   

Question: 2 -Mark ‘T’ if the statement is true and ‘F’ if it is false:

1. We can obtain an enlarged and erect image by a convex mirror.
   (F)
2. A concave lens always form a virtual image.
   (T)
3. We can obtain a real, enlarged and inverted image by a concave mirror.
   (F)
4. A real image cannot be obtained on a screen.
   (F)
5. A concave mirror always form a real image.
   (F)

Question: 3 -Match the items given in Column I with one or more items of Column II.
Question: 4 -State the characteristics of the image formed by a plane mirror.

Answer: In case of plane mirror, the image is erect, virtual and of same size as the object.

Question: 5 -Find out the letters of English alphabet or any other language known to you in which the image formed in a plane mirror appears exactly like the letter itself. Discuss your findings.

Answer: Some examples: A, H, I, M, O, T, U, V, W and X

Question: 6 -What is a virtual image? Give one situation where a virtual image is formed.

Answer: The image which cannot be obtained on a screen is called virtual image. For example, virtual image is always formed in case of plane mirror and convex mirror.

Question: 7 -State two differences between a convex and a concave lens.

Answer: A convex lens can make enlarged image, while a concave lens would always make smaller image. A convex lens usually makes real image, while a concave lens always makes a virtual image.

Question: 8 -Give one use each of a concave and a convex mirror.

Answer: (a) Concave mirror is used in solar furnace. (b) Convex mirror is used in rear view mirrors.

Question: 9 -Which type of mirror can form a real image?

Answer: Concave mirror

Question: 10 - Which type of lens forms always a virtual image?

Answer: Concave lens

Choose the correct option in questions 11–13
Question: 11 - A virtual image larger than the object can be produced by a

1. Concave lens
2. Concave mirror
3. Convex mirror
4. Plane mirror

Answer: (c) Concave mirror

David is observing his image in a plane mirror. The distance between the mirror and his image is 4 m. If he moves 1 m towards the mirror, then the distance between David and his image will be

1. 3 m
2. 5 m
3. 6 m
4. 8 m

Answer: (a) 3 m

Question: 13 -The rear view mirror of a car is a plane mirror. A driver is reversing his car at a speed of 2 m/s. The driver sees in his rear view mirror the image of a truck parked behind his car. The speed at which the image of the truck appears to approach the driver will be

1. 1 m/s
2. 2 m/s
3. 4 m/s
4. 8 m/s

Answer: (b) 2 m/s

Ch 14 : Electric Current and Its Effects

               Electric Current and Its Effects

 

Question: 1 - Draw in your notebook the symbols to represent the following components of electrical circuits: connecting wires, switch in the ‘OFF’ position, bulb, cell, switch in the ‘ON’ position, and battery.

Answer:

Question: 2 - Draw the circuit diagram to represent the circuit shown in the following figure.

Answer:

Question: 3 - The following figure shows four cells fixed on a board. Draw lines to indicate how you will connect their terminals with wires to make a battery of four cells.

Answer:

Question: 4 - The bulb in the circuit shown in the following figure does not glow. Can you identify the problem? Make necessary changes in the circuit to make the bulb glow.

Answer: The positive terminals of both the cells are together and that is why the bulb is not glowing. The cells should be kept in a way that the positive terminal of one cell is near the negative terminal of another cell; to make the bulb glow.

Question: 5 - Name any two effects of electric current.

Answer: The two effects of electric current are; heating effect and magnetic effect.

Question: 6 - When the current is switched on through a wire, a compass needle kept nearby gets deflected from its north-south position. Explain.

Answer: This happens because when electric current passes through a conducting wire, a magnetic field is created around the wire. The magnetic field causes deflection in the magnetic compass.

Question: 7 - Will the compass needle show deflection when the switch in the circuit shown by following figure is closed?

Answer: Yes

Question: 8 - Fill in the blanks:

1. Longer line in the symbol for a cell represents its …………..terminal.
   
   Answer: Positive
   
2. The combination of two or more cells is called a ……………
   
   Answer: Battery
   
3. When current is switched ‘on’ in a room heater, it ……………….
   
   Answer: heats up
   
4. The safety device based on the heating effect of electric current is called a ……………
   
   Answer: Electric fuse

Question: 9 - Mark ‘T’ if the statement is true and ‘F’ if it is false:

1. To make a battery of two cells, the negative terminal of one cell is connected to the negative terminal of the other cell. (F)
2. When the electric current through the fuse exceeds a certain limit, the fuse wire melts and breaks. (T)
3. An electromagnet does not attract a piece of iron. (F)
4. An electric bell has an electromagnet. (T)

Question: 10 - Do you think an electromagnet can be used for separating plastic bags from a garbage heap? Explain.

Answer: Since plastic is a non-magnetic material, so electromagnet cannot be used to separate plastic bags from a garbage heap.

Question: 11 - An electrician is carrying out some repairs in your house. He wants to replace a fuse by a piece of wire. Would you agree? Give reasons for your response.

Answer: A special wire with low melting point should be used for the fuse wire and any other wire would not serve the purpose. Hence, I would not agree with the electrician.

Question: 12 - Zubeda made an electric circuit using a cell holder shown in Fig. 14.4 (in the chapter), a switch and a bulb. When she put the switch in the ‘ON’ position, the bulb did not glow. Help Zubeda in identifying the possible defects in the circuit.

Answer: There can following possibilities:

• The terminals of cells are not in correct position.
• The connections are loose.
• The bulb may have fused.

Question: 13 -In the circuit shown in the following figure:

1. Would any of the bulb glow when the switch is in the ‘OFF’ position?
   
   Answer: None of the bulbs would glow.
   
2. What will be the order in which the bulbs A, B and C will glow when the switch is moved to the ‘ON’ position?
   
   Answer: All the bulbs would glow at once.

 

Ch 13 : Motion and Time

                                           Motion and Time

 

Question: 1. Classify the following as motion along a straight line, circular or oscillatory motion:
(i) Motion of your hands while running.
(ii) Motion of a horse pulling a cart on a straight road.
(iii) Motion of a child in a merry-go-round.
(iv) Motion of a child on a see-saw.
(v) Motion of the hammer of an electric bell.
(vi) Motion of a train on a straight bridge.

Answer: (i) Periodic motion or Oscillatory motion

(ii) Along a straight line (Linear motion)

(iii) Circular motion

(iv) Periodic motion or oscillatory motion

(v) Periodic motion or oscillatory motion

(vi) Linear motion

Question: 2. Which of the following are not correct?
(i) The basic unit of time is second.
(ii) Every object moves with a constant speed.
(iii) Distances between two cities are measured in kilometres.
(iv) The time period of a given pendulum is not constant.
(v) The speed of a train is expressed in m/h.

Answer: (ii), (iv) and (v)

Question: 3. A simple pendulum takes 32 s to complete 20 oscillations. What is the time period of the pendulum?

Answer:

Given, Number of oscillation = 20

Time taken = 32 second

We know that,

Question: 4. The distance between two stations is 240 km. A train takes 4 hours to cover this distance. Calculate the speed of the train.

Answer: Given, distance = 240 km

Time taken = 4 hour

We know that,

Question: 5. The odometer of a car reads 57321.0 km when the clock shows the time 08:30 AM. What is the distance moved by the car, if at 08:50 AM, the odometer reading has changed to 57336.0 km? Calculate the speed of the car in km/min during this time. Express the speed in km/h also.

Answer:

Given,

Initial reading of odometer = 57321.0 km

Final reading of odometer = 57336.0 km

Initial time = 08:30 AM

Final time = 08:50 AM

Thus,

Distance covered = Final reading of odometer – Initial reading of odometer

  = 57336.0 km – 57321.0 km = 15 km

Total time taken = Final time – Initial time = 08:50 AM – 08:30 AM = 20 minute

So, speed = 0.75 km/minute or 45km/hour

Question: 6. Salma takes 15 minutes from her house to reach her school on a bicycle. If the bicycle has a speed of 2 m/s, calculate the distance between her house and the school.

Answer:

Given, Speed = 5 m/s

Time taken = 15 minute

Distance =?

We know that,

Question: 7. Show the shape of the distance-time graph for the motion in the following cases:
(i) A car moving with a constant speed.
(ii) A car parked on a side road.

Answer:

Question: 8. Which of the following relations is correct?
Question: 9. The basic unit of speed is:
(i) km/min (ii) m/min (iii) km/h (iv) m/s

Answer: (iv) m/s

Question: 10. A car moves with a speed of 40 km/h for 15 minutes and then with a speed of 60 km/h for the next 15 minutes. The total distance covered by the car is:
(i) 100 km (ii) 25 km (iii) 15 km (iv) 10 km

Answer:

Given,

Speed for first 15 minute = 40km/h

Speed for next 15 minute = 60 km/h

We know that,

Distance = Speed X Time

Therefore, Distance covered in first 15 minute i.e. 0.25 hour = 40 km/h X 0.24 hour = 10 km

Distance covered in next 15 minute = 60 km/h X 0.25 hour = 15 km

Thus, total distance covered = 10 km + 15 km = 25 km

Hence, Answer (ii) is correct

Question: 11. Suppose the two photographs, shown in Fig. 13.1 and Fig. 13.2 had been taken at an interval of 10 seconds. If a distance of 100 metres is shown by 1 cm in these photographs, calculate the speed of the blue car.

Answer:

Figure in question is given from text book.

Do the following steps to calculate the speed:

Measure the distance cover by blue car.

Multiply the distance measured in cm by 100 to get the distance covered by car in meter.

Divide th distance in meter by 10 second (time given in question).

Result will be the speed of car in meter/second.

Suppose the distance of car is 3.5 cm.

Thus, Distance covered by car = 3.5 x 100 = 350 meter.

Time (given in question) = 10 second

Question: 12. Figure given here shows the distance-time graph for the motion of two vehicles A and B. Which one of them is moving faster?

Answer: Vehicle A is moving faster which is evident from higher slope for distance time graph of this vehicle; compared to that of the other vehicle.

Question: 13. Which of the following distance-time graphs shows a truck moving with speed which is not constant?

Answer: (iii) The slope of the graph in this option is not a straight line and hence it does not show a uniform motion.

 

Ch 12 : REPRODUCTION IN PLANTS

                          REPRODUCTION IN PLANTS

 

Q1. Describe the different methods of asexual reproduction . Give examples.
A.There are different methods by which plants reproduce asexually. They are vegetative propagation, budding,fragmentation and spore formation. The vegetative parts of a plant are the roots, stems and leaves. When new plants are produced from these parts, the process is called vegetative propagation.
1. Budding- A bulb like projection grows on the parent organism. It grows and may eventually break away from the parent. E.g. yeast, hydra, corals, sponges.
2. Fragmentation- The organism breaks up into two or more fragments after maturation. These fragments grow into new individuals. E.g. spirogyra, hydra
3. Spore formation- A spore is a tiny, spherical and unicellular body protected by a thick wall. Under favourable conditions, a spore germinates and develops into a new individual. E.g. mosses, ferns, moulds Q2. Describe the various ways by which seeds are dispersed.
A. Seeds and fruits are dispersed by agents like wind, water, animals and humans.
The pods present in these seeds dry up in the sun. This causes the pod to split with great force, thereby dispersing the seeds away from the parent plant.
Some seeds are dispersed by a special method called explosion. Examples are mustard, ladies finger, peas, bean, pod and castor. Q3. How is fertilization brought about in a flower?
A. The zygote is formed by the fusion of the male and female gametes. This process is called fertilisation. After fertilisation, the ovary changes into a fruit. It may be either fleshy or dry. Q4. Write 4 advantages of vegetative propagation.
A.The advantages are- 1. New plants can be produced quickly.
2. The plants so produced are exact copies of parent plants
3. Seedless plants can be easily propagated. Q5. Differentiate between:- 1. unisexual flowers and bisexual flowers-
Bisexual flowers contain both – the stamens and the pistil. For example, mustard and rose.
Unisexual flowers have either the stamens or the pistil. For example, cucumber, maize and watermelon 2. sexual and asexual reproduction
In sexual reproduction, the male and the female gametes fuse to form seeds that eventually develop into new plants.
The seeds are formed inside the fruit. On the other hand, in asexual reproduction, a new plant is grown from any part of a plant other than the seeds. 3. cross pollination and self pollination

The transfer of pollen grains from the anther of one flower, to the stigma of another flower on another plant of  the same type, is known as cross-pollination.
The transfer of pollen grains from the anther to the stigma of the same flower or to the stigma of another flower on the same plant, it is termed self-pollination.
Q6. Why are flowers known as reproductive parts of a plant?
A.flowers are known as reproductive parts of a plant as flowers contain both male and female reproductive structures as  stamen and pistil respectively.
Q7. What is the significance of dispersal of seeds and fruits?
A. A plant produces a large number of seeds. They are required to be dispersed properly to get enough space, water and minerals and sunlight to grow healthy.
Q8. Why do spores can survive for a long time?
A. Spores are protected within a thick wall that makes it withstand unfavourable and extreme climate.
Q9. Which take less time to grow and bear flowers and fruits, plants produced by vegetative propagation or from seeds? Why?
Ans: A plant produced by vegetative propagation takes less time to develop and bear fruits and flowers. Plants grown from seeds require more attention and take good time to germinate and grow.
Q10. Write a short note on pollination.
A. It is the transfer of pollen grains from an anther to the stigma. Insects, birds and other animals help in cross pollination of flowers. Insects are attracted by the colour and scent of petals. Winds can also blow pollen grains. Such flowers such plants have flowers with small petals or with no petals at all.
Q11. Describe the process of seed formation.
A. After fertilization, petals, sepals and stamen wither away and fall off. Style and stigma also fall off. The ovule walls develop hard layers and seed develop. Each seed contains embryo enclosed in a protective seed coat.
Q12. Explain the process of fruit formation.
A. The ovary begins to swell. In time it becomes a fruit. So, a fruit is actually a developed ovary. Some fruits, like mangoes and apples are sweet and juicy. Sometimes, they become hard and woody forming the shells of nuts.
Q13. What are characteristics of seeds dispersed by water.
A. Seeds develop floating ability in the form of spongy or fibrous outer coat. E.g. coconut seeds have a thick coat of fiber that enables it to float in water. Lotus fruit has a spongy part that enables it to float.
Q 14.Define reproduction.

Ans:Reproduction is life process of producing new individuals from their parents of its own kinds. Q.15. What do you understand by the term 'leaf venetion'? What are the two types of leaf venetion?
Ans: The arrangement of veins in a leaf is called the leaf venation.

Reticulate Venation :In this the veins form a network like structure

Parallel venation : In this the veinsrun paralell to each other

 

Ch 11 : Transportation in Animals and Plants

                         Transportation in Animals and Plants

 

Question: 1 - Match structures given in Column I with functions given in Column II.
2 - Fill in the blanks.
(i) The blood from the heart is transported to all parts of the body by the ………….

Answer: Heart

(ii) Haemoglobin is present in ………….cells.

Answer: Red Blood

(iii) Arteries and veins are joined by a network of …………

Answer: Capillaries

(iv) The rhythmic expansion and contraction of the heart is called…………..

Answer: Heart Beat

(v) The main excretory product in human beings is ………………

Answer: Urea

(vi) Sweat contains water and …………….

Answer: Waste products

(vii) Kidneys eliminate the waste materials in the liquid form called …………..

Answer: Urine

(viii) Water reaches great heights in the trees because of suction pull caused by ………..

Answer: Transpiration

Question: 3 - Choose the correct options:
(a) In plants, water is transported through
(i) Xylem
(ii) Phloem
(iii) Stomata
(iv) Root hair

Answer: (i) Xylem

(b) Water absorption through roots can be increased by keeping the plants
(i) in the shade
(ii) in dim light
(iii) under the fan
(iv) covered with a polythene bag

Answer: (iii) Under the fan

Question: 4 - Why is transport of materials necessary in a plant or in an animal? Explain.

Answer: The cells of plants and animals need various substances to carry out important metabolic activities. Further, many waste products are created during these metabolic activities. Transport of materials is necessary to supply the various substances and to remove the waste products.

Question: 5 - What will happen if there are no platelets in the blood?

Answer: Platelets are responsible for clotting of blood. If there are no platelets, the blood would not clot in case of an injury. This will lead to excess blood loss and finally in death of the person.

Question: 6 - What are stomata? Give two functions of stomata.

Answer: The numerous pores on the surface of leaf are called stomata. Transpiration and exchange of gases (carbon dioxide and oxygen) are some of the functions of stomata.

Question: 7 - Does transpiration serve any useful function in the plants? Explain.

Answer: Transpiration serves important functions in plants. Transpiration creates the transpiration pull; which is responsible for the rise of water to great heights in tall plants and other trees.

Question: 8 - What are the components of blood?

Answer: The main components of blood are: Plasma, Blood Cells and Platelets.

Question: 9 - Why is blood needed by all the parts of a body?

Answer: Blood acts as a carrier of various substances. Every part of the body needs certain substances to perform its functions. Additionally, every part creates some waste products. Blood is needed by all parts of the body so that various substances can be supplied to them and waste can be removed from them.

Question: 10 - What makes the blood look red?

Answer: Blood is red because of the presence of a pigment; called haemoglobin.

Question: 11 - Describe the function of the heart.

Answer: The heart is a pumping organ which pumps the blood. The heart pumps the deoxygenated blood to the lungs; for oxygenation. Moreover, the heart pumps the oxygenated blood to different parts of the body.

Question: 12 - Why is it necessary to excrete waste products?

Answer: Waste products can prove lethal if not removed in time. Hence, it is necessary to excrete the waste products.

 

Ch 10 : Respiration in Organism

                                                                  Respiration in Organism

 

Question: 1 - Why does an athlete breathe faster and deeper than usual after finishing the race?
Answer: When the athlete runs in the race, his body needs more oxygen. His rate of breathing increases so that more oxygen can be supplied to the body. This is the reason, an athlete needs to breathe faster and deeper than usual; after finishing the race.
Question: 2 - List the similarities and differences between aerobic and anaerobic respiration.
Answer: The similarities and differences between aerobic and anaerobic respiration are as follows:
Similarities: Food is oxidized in both cases and energy is released.
Differences: Carbon dioxide and water are the end products of aerobic respiration, while alcohol or lactic acid is the end product of anaerobic respiration. Aerobic respiration is more efficient than anaerobic respiration.
Question: 3 - Why do we often sneeze when we inhale a lot of dust-laden air?
Answer: When dust particles enter our nostril, it triggers a message to the brain. The brain instructs the nasal chamber to initiate sneezing. This is a method to remove the unwanted dust particles from the nostrils. Sneezing is a type of defense mechanism used by our body.
Question: 4 - Take three test-tubes. Fill each of them with water. Label them A, B and C. Keep a snail in test-tube A, a water plant in test-tube B and in C, keep snail and plant both. Which test-tube would have the highest concentration of CO2?
Answer: The test tube A will have the highest concentration of carbon dioxide. The carbon dioxide comes because of respiration by the snail. In test tubes B and C; a part of the carbon dioxide is utilized by the plant for photosynthesis and hence there is less concentration of carbon dioxide.
Question: 5 - Tick the correct answer:
  (a) In cockroaches, air enters the body through

1.  lungs
2.  gills
3.  spiracles
4.  skin

Answer: (iii) Spiracles
  (b) During heavy exercise, we get cramps in the legs due to the accumulation of

1. carbon dioxide
2.  lactic acid
3.  alcohol
4.  water

Answer: (ii) Lactic acid
  (c)  Normal range of breathing rate per minute in an average adult person at rest is

1. 9–12
2.  15–18
3. 21–24
4. 30–33

Answer: (ii) 15 – 18
   (d) During exhalation, the ribs

1. move outwards
2. move downwards
3.  move upwards
4. do not move at all

Answer: (ii) Move downwards
Question: 6 - Match the items in Column I with those in Column II:

Question: 7 - Mark ‘T’ if the statement is true and ‘F’ if it is false:

1. During heavy exercise the breathing rate of a person slows down. (F)
2.  Plants carry out photosynthesis only during the day and respiration only at night. (F)
3.  Frogs breathe through their skins as well as their lungs. (T)
4.  The fishes have lungs for respiration. (F)
5. The size of the chest cavity increases during inhalation. (T)

Question: 9 - The mountaineers carry oxygen with them because:

1. At an altitude of more than 5 km there is no air.
2. The amount of air available to a person is less than that available on the ground.
3. The temperature of air is higher than that on the ground.
4. The pressure of air is higher than that on the ground.

 

Ch 9 : Soil

                                                                                  Soil

Question: 1. In addition to the rock particles, the soil contains
(i) air and water
(ii) water and plants
(iii) minerals, organic matter, air and water
(iv) water, air and plants

Answer: (iii) minerals organic matter, air and water

Question: 2. The water holding capacity is the highest in
(i) sandy soil
(ii) clayey soil
(iii) loamy soil
(iv) mixture of sand and loam

Answer: (ii) Clayey soil

Question: 3. Match the items in Column I with those in Column II:
Question: 4. Explain how soil is formed.

Answer: Soil is formed by the process of weathering. The breaking down of rocks because of the action of wind, rain, ice, etc. is called weathering.

Question: 5. How is clayey soil useful for crops?

Answer: Clayey soil can retain much water and consequently contains lot of moisture even in summer. That’s why it is most useful for crops like paddy which requires lot of water. Clayey soil is useful for wheat also.

Question: 6. List the differences between clayey soil and sandy soil.

Answer:

Question: 8. Razia conducted an experiment in the field related to the rate of percolation. She observed that it took 40 min for 200 mL of water to percolate through the soil sample. Calculate the rate of percolation.

Answer:

Given, Time = 40 minute

VolumeVolume of water = 200 ml

Question: 9. Explain how soil pollution and soil erosion could be prevented.

Answer: Soil pollution and soil erosion could be prevented using following:

Plantation

Better farming method, like crop rotation and mixed farming

Use of manure instead of synthetic fertilization.

Use of natural pesticides.

Avoid dumping non-biodegradable items in soil.

Terrace farming in hilly areas.

Ch 8 : Wind, Strom And Cyclone

                              Wind, Strom And Cyclone

 

Question: 1. Fill the missing word in the blank spaces in the following statements:
(a) Wind is——————air.

Answer: Moving

(b) Winds are generated due to——————heating on the earth.

Answer: Uneven

(c) Near the earth’s surface __________air rises up whereas ___________ air comes down.

Answer: Warm, cold

(d) Air moves from a region of ——— pressure to a region of——— pressure.

Answer: High, Low

Question: 2. Suggest two methods to find out wind direction at a given place.

Answer: Two methods to find the direction of wind:

(a) Take a handful of sand or dust. Release it slowly from a height and observe the direction in which the falling sand is moving. This will show the direction of wind.

(b) Tie a thin plastic sheet or cloth with a stick. Keep the stick at a place which is as high as possible. The direction in which the cloth sways shows the direction of wind.

Qeustion: 3. State two experiences that made you think that air exerts pressure (other than those given in the text).

Answer: I have seen paratroopers jumping from aeroplanes. The parachute helps them in reaching the ground safely. The air pressure reduces the speed of the parachute and the paratrooper lands without getting injured.

Question: 4. You want to buy a house. Would you like to buy a house having windows but no ventilators? Explain your answer.

Answer: A house should have ventilators along with windows. The warm air would rise up and exit from the ventilators. The cooler air would rush in through the windows. This will help in making the rooms comfortable. A room without ventilators shall not be cooled as efficiently as one with ventilators.

Question: 5. Explain why holes are made in hanging banners and hoardings.

Answer: Banners and hoardings are usually very large. The air pressure; because of the moving air; can blow away the banners. Holes are made in banners and hoardings so that the wind can move through them. This helps in reducing the impact of air pressure on the hoardings and thus they are not get blown away.

Question: 6. How will you help your neighbours in case cyclone approaches your village/town?

Answer: I will take following steps to help my neighbours in case of cyclone:

• I will help people to reach to a safer place.
• I will organize a community kitchen during the stress period.
• I will provide first aid to injured people.
• I will also arrange for safe drinking water for the people.

Question: 7. What planning is required in advance to deal with the situation created by a cyclone?

Answer: Following planning is required to deal with the situation created by a cyclone:

• Proper shelters should be built by the government agencies so that people can be accommodated in them.
• Alternate arrangements of seamless communication among rescue agencies should be made.
• Proper stock of emergency medicines should be kept.
• Proper arrangements of safe drinking water should be made.
• Government should chalk out a rehabilitation plan for those affected by cyclone.

Question: 8. Which one of the following place is unlikely to be affected by a cyclone.
(i) Chennai (ii) Mangaluru (Mangalore) (iii) Amritsar (iv) Puri

Answer: (iv) Puri

Question: 9. Which of the statements given below is correct?

1. In winter the winds flow from the land to the ocean.
2. In summer the winds flow from the land towards the ocean.
3. A cyclone is formed by a very high-pressure system with very high-speed winds revolving around it.
4. The coastline of India is not vulnerable to cyclones.

Answer: (i) In winter the winds flow from the land to the ocean

 

Ch 7 : Weather, Climate and Adaptation of Animals to Climate

        Weather, Climate and Adaptation of Animals to Climate

 

Question: 1- Name the elements that determine the weather of a place.

Answer: Temperature, humidity, rainfall and wind speed are the elements that determine the weather of a place.

Question:2. When are the maximum and minimum temperature likely to occur during the day?

Answer: The temperature is minimum in the morning and maximum at the noon.

Question:3. Fill in the blanks:
(i) The average weather taken over a long time is called __________.

Answer: (i) Climate

(ii) A place receives very little rainfall and the temperature is high throughout the year, the climate of that place will be ___________ and ___________ .

Answer: (ii) Hot and Dry.

(iii) The two regions of the earth with extreme climatic conditions are ___________ and __________.

Answer: Polar region and desert

Question:4. Indicate the type of climate of the following areas:
(a) Jammu and Kashmir: _________________________________

Answer: Moderately hot and wet.

(b) Kerala: ____________________________________________

Answer: Hot and wet

(c) Rajasthan: __________________________________________

Answer: Hot and dry

(d) North-east India: _____________________________________

Answer: hot and wet

Question:5. Which of the two changes frequently, weather or climate?

Answer: Weather.

Question:6. Following are some of the characteristics of animals:
For each characteristic indicate whether it is adaptation for tropical rainforests or polar regions. Do you think that some of these characteristics can be adapted for both regions?

Answer:

Question:7. The tropical rainforest has a large population of animals. Explain why it is so.

Answer: Dense forest provides large amount and variety of food. This supports a large population to survive in the rain forest.

Question:8. Explain, with examples, why we find animals of certain kind living in particular climatic conditions.

Answer: Animals of certain kinds have adaptations for a particular climate. Due to this, some animals are fit to live in a particular type of climate only. Hence some animals live in some selected climate only.

Question:9. How do elephant living in the tropical rainforest adapt itself.

Answer: Adaptations seen in elephants:

Elephants have well developed sense of smell. It helps the elephant in finding the food. The trunk has powerful muscles which help the elephant in uprooting even a big tree. Elephants have good sense of hearing which help the elephant in sensing danger way in advance. An elephant uses its trunk to sprinkle water all over its body so that it can cool down its body temperature.

Choose the correct option which answers the following question:
Question:10. A carnivore with stripes on its body moves very fast while catching its prey. It is likely to be found in
(i) polar regions
(ii) deserts
(iii) oceans
(iv) tropical rainforests

Answer: (iv) Tropical rainforests

11. Which features adapt polar bears to live in extremely cold climate?
(i) A white fur, fat below skin, keen sense of smell.
(ii) Thin skin, large eyes, a white fur.
(iii) A long tail, strong claws, white large paws.
(iv) White body, paws for swimming, gills for respiration.

Answer: (i) A white fur, fat below skin, keen sense of smell.

12. Which option best describes a tropical region?
(i) hot and humid
(ii) moderate temperature, heavy rainfall
(iii) cold and humid
(iv) hot and dry

Answer: (i) hot and humid

 

Ch 6 : Physical and Chemical Changes

                                                      Physical and Chemical Changes

 

1. Classify the changes involved in the following processes as physical or chemical changes:

(a) Photosynthesis

(b) Dissolving sugar in water

(c) Burning of coal

(d) Melting of wax

(e) Beating aluminium to make aluminium foil

(f ) Digestion of food

Answer:

(a) Chemical change.

(b) Physical change.

(c) Chemical change

(d) Physical change

(e) Physical change

(f) Chemical change

2. State whether the following statements are true or false. In case a statement is false, write the corrected statement in your notebook.

(a) Cutting a log of wood into pieces is a chemical change. (True/False)

(b) Formation of manure from leaves is a physical change. (True/False)

(c) Iron pipes coated with zinc do not get rusted easily. (True/False)

(d) Iron and rust are the same substances. (True/False)

(e) Condensation of steam is not a chemical change. (True/False)

Answer:

(a) False (b) False (c) True (d) False (e) True

3. Fill in the blanks in the following statements:

(a) When carbon dioxide is passed through lime water, it turns milky due to the formation of _________.

Answer: Calcium carbonate.

(b) The chemical name of baking soda is _________.

Answer: Sodium hydrogen carbonate.

(c) Two methods by which rusting of iron can be prevented are _________ and _________.

Answer: Polishing, Glavanisation.

(d) Changes in which only _________ properties of a substance change are called physical changes.

Answer: Physical

(e) Changes in which new substances are formed are called _________ changes.

Answer: Chemical

4. When baking soda is mixed with lemon juice, bubbles are formed with the evolution of a gas. What type of change is it? Explain.

Answer: When baking soda is mixed with lemon juice, bubbles formed because of evolution of carbon dioxide gas. This is a chemical change, because in this reaction new substances are formed.

5. When a candle burns, both physical and chemical changes take place. Identify these changes. Give another example of a familiar process in which both the chemical and physical changes take place.

Answer: In burning of candle some of the wax melts, which is physical change, while most of the wax burnt, which is a chemical change.

In the burning of wood, water present in wood changes into vapour, this is physical change, while burning of wood is a chemical change.

6. How would you show that setting of curd is a chemical change?

Answer: In the setting of curd, milk changes into new substance, curd. This is an irreversible process that means milk cannot get back from curd. Formation of new substance and irreversible process shows that setting of curd is a chemical change.

7. Explain why burning of wood and cutting it into small pieces are considered as two different types of changes.

Answer: In burning of wood, new substances are formed and hence is a chemical change. While cutting the wood into small pieces no new substance is formed, thus it is a physical change.

Hence, burning of wood and cutting it into small pieces are considered as two different types of changes.

8. Describe how crystals of copper sulphate are prepared.

Answer:

Process:

• Water is taken in a beaker.
• Few drops of sulphuric acid is added to the water.
• Water is let to boil.
• When water starts boiling, copper sulphate powder is added to the water with continuous stirring the solution.
• When copper sulphate starts deposited into bottom of the beaker, then solution is filtered and left for cooling.
• After cooling, the crystals of copper sulphate is prepared.

9. Explain how painting of an iron gate prevents it from rusting.

Answer: Iron get rusted because of reaction with oxygen present in moist air. By painting iron gate, iron is prevented to come into contact with oxygen present in moist air, which prevent it be getting rusted.

10. Explain why rusting of iron objects is faster in coastal areas than in deserts.

Answer: Iron get rusted because of reaction with oxygen present in moist air. In coastal areas, air contains more moisture because of sea or ocean, while in deserts air is dry and hot. Thus because of getting more moist air iron objects getting rusted faster in coastal areas than in deserts.

11. The gas we use in the kitchen is called liquified petroleum gas (LPG). In the cylinder it exist as a liquid. When it comes out from the cylinder it becomes a gas (Change – A) then it burns (Change – B). The following statements pertain to these changes. Choose the correct one.

(i) Process – A is a chemical change.

(ii) Process – B is a chemical change.

(iii) Both processes A and B are chemical changes.

(iv) None of these processes is a chemical change.

Answer: (ii) Process – B is a chemical change.

12. Anaerobic bacteria digest animal waste and produce biogas (Change – A). The biogas is then burnt as fuel (Change – B). The following statements pertain to these changes. Choose the correct one.

(i) Process – A is a chemical change.

(ii) Process – B is a chemical change.

(iii) Both processes A and B are chemical changes.

(iv) None of these processes is a chemical change.

Answer: (iii) Both processes A and B are chemical changes.

 

Ch 5 : Acid Base And Salt

                                                                      Acid Base And Salt

Question: 1. State differences between acids and bases.

Answer:

Question: 2. Ammonia is found in many household products, such as window cleaners. It turns red litmus blue. What is its nature?

Answer:Since window cleaner turns red litmus paper to blue, it is basic in nature.

Question:3. Name the source from which litmus solution is obtained. What is the use of this solution?

Answer:

Litmus solution is obtained from lichens. Litmus solution is used to detect the acidic and basic characteristic of a substance.

Question: 4. Is the distilled water acidic/basic/neutral? How would you verify it?

Answer:Distilled water is neutral in character, i.e. it is neither acidic nor basic.

Neutral nature of distilled water can be verified by the use of blue and red litmus paper.

Distilled water does not change the colour of either blue or red litmus paper.

Question: 5. Describe the process of neutralization with the help of an example.

Answer:When the solution of acid is mixed with the solution of base in proper ratio, both of them neutralize the effect of each other and a new substance; called salt; is formed; along with water. This is called neutralization or neutralization reaction.

Example: When the solution of sodium hydroxide (a base) is mixed with the solution of hydrochloric acid (an acid) in proper ratio, both neutralize each other and the reaction mixture so obtained is neutral in character. In this reaction, a new substance sodium chloride (common salt) is formed.

The reaction involved in this can be written as follows:

Question: 6. Mark ‘T’ if the statement is true and ‘F’ if it is false:
(i) Nitric acid turns red litmus blue. (T/F)

Answer:F

(ii) Sodium hydroxide turns blue litmus red. (T/F)

Answer:F

(iii) Sodium hydroxide and hydrochloric acid neutralize each other and form salt and water. (T/F)

Answer:T

(iv) Indicator is a substance which shows different colours in acidic and basic solutions. (T/F)

Answer:F

(v) Tooth decay is caused by the presence of a base. (T/F)

Answer:F

Question: 7. Dorji has a few bottles of soft drink in his restaurant. But, unfortunately, these are not labeled. He has to serve the drinks on the demand of customers. One customer wants acidic drink, another wants basic and third one wants neutral drink. How will Dorji decide which drink is to be served to whom?

Answer:

Dorji would dip blue and red litmus paper in the sample of each of the bottles.

Sample of solution of bottle which turns blue litmus paper red is acidic.

Sample of solution of bottle which turns red litmus paper blue is basic.

Sample of solution of bottle which does not change the colour of either blue or red litmus paper is neutral in nature.

After detecting the acidic, basic and neutral nature of soft drink, Dorji would serve the drink to the customers according to their requirement.

Question: 8. Explain why:
(a) An antacid tablet is taken when you suffer from acidity.

Answer:

Antacid means substance that works against acid. Antacid tablet is taken in the case of acidity to neutralize the excess acid produced in the stomach.

Antacid tablets neutralize the acid produced in the stomach and give relief from acidity.

(b) Calamine solution is applied on the skin when an ant bites.

Answer:Calamine solution, which is zinc carbonate, is a base. In the case of ant bites, ant injects an acid; called formic acid; in the skin which causes pain and irritation. By applying calamine solution, it neutralizes the effect of acid inject in the course of ant bite and gives relief from pain.

(c) Factory waste is neutralized before disposing it into the water bodies.

Answer:

Most of the factory wastes contain acid. It they are flushed into water as they are, then acid present in them would kill the aquatic organisms; along with creating pollution. Thus, it is necessary to neutralize the factory waste before disposing it into the water bodies.

Question: 9. Three liquids are given to you. One is hydrochloric acid, another is sodium hydroxide and third is a sugar solution. How will you identify them? You have only turmeric indicator.

Answer:

Label the test tubes as A, B and C.

Dip the turmeric indicator in test tube A. If the turmeric paper changes to red then the liquid in the test tube is sodium hydroxide; which is a base. Otherwise, it is either hydrochloric acid or sugar solution; which is neutral.

If the liquid in the test tube A is not sodium hydroxide then keep it aside and repeat above procedure with the test tube B. If it is not sodium hydroxide then the liquid in test tube C must be sodium hydroxide.

Take aside the test tube with sodium hydroxide and pour sodium hydroxide in remaining two test tubes. The test tube which becomes warm contains acid. When acid and base neutralize each other, heat is released in the process.

Question: 10. Blue litmus paper is dipped in a solution. It remains blue. What is the nature of the solution? Explain.

Answer:If blue litmus paper is dipped in a solution and it would remain blue then the solution may be basic or neutral in character.

Blue litmus paper does not change its colour with basic solution and neutral solution.

Question: 11. Consider the following statements:
(a) Both acids and bases change colour of all indicators.
(b) If an indicator gives a colour change with an acid, it does not give a change with a base.
(c) If an indicator changes colour with a base, it does not change colour with an acid.
(d) Change of colour in an acid and a base depends on the type of the indicator.
Which of these statements are correct?
(i) All four (ii) a and d (iii) b and c (iv) only d

Answer:(iv) only d

Ch 4 : Heat

                                                                      Heat

Question: 1 - State similarities and differences between the laboratory thermometer and the clinical thermometer.

Answer:

Question: 2 - Give two examples each of conductors and insulators of heat.

Answer:

Examples of conductor: Iron, copper
Examples of insulator: Rubber, plastic
Question: 3 - Fill in the blanks:
(a) The hotness of an object is determined by its __________.

Answer: Temperature.

(b) Temperature of boiling water cannot be measured by a _____________ thermometer.

Answer: Clinical Thermometer

(c) Temperature is measured in degree ______________.

Answer: Celsius

(d) No medium is required for transfer of heat by the process of __________.

Answer: Radiation

(e) A cold steel spoon is dipped in a cup of hot milk. It transfers heat to its other end by the process of ______________.

Answer: Conduction.

(f ) Clothes of ______________ colours absorb heat better than clothes of light colours.

Answer: Dark

Question: 4 - Match the following :
Question: 5 - Discuss why wearing more layers of clothing during winter keeps us warmer than wearing just one thick piece of clothing?

Answer: By wearing more layers of clothing, air gets trapped between different layers. This makes different layers of insulation and thus provides better protection against cold. On the other hand, wearing just one piece of clothing creates just one insulator layer and hence is less effective in beating the cold.

Question: 6 - Look at Fig. 4.13 (in NCERT Text Book). Mark where the heat is being transferred by conduction, by convection and by radiation.

Answer: 

Question: 7 - In places of hot climate it is advised that the outer walls of houses be painted white. Explain.

Answer: White colour reflects most of the heat falling on it. This makes the house colder. Thus, in places of hot climate it is advised that the outer walls of house be painted white.

Question: 8 - One litre of water at 30°C is mixed with one litre of water at 50°C. The temperature of the mixture will be
(a) 80°C
(b) more than 50°C but less than 80°C
(c) 20°C
(d) between 30°C and 50°C

Answer: (d) between 30°C and 50°C

Question: 9 - An iron ball at 40°C is dropped in a mug containing water at 40°C. The heat will
(a) flow from iron ball to water.
(b) not flow from iron ball to water or from water to iron ball.
(c) flow from water to iron ball.
(d) increase the temperature of both.

Answer: (b) not flow from iron ball to water or from water to iron ball.

Question: 10 - A wooden spoon is dipped in a cup of ice cream. Its other end
(a) becomes cold by the process of conduction.
(b) becomes cold by the process of convection.
(c) becomes cold by the process of radiation.
(d) does not become cold.

Answer: (d) does not become cold.

Question : 11 - Stainless steel pans are usually provided with copper bottoms. The reason for this could be that
(a) copper bottom makes the pan more durable.
(b) such pans appear colourful.
(c) copper is a better conductor of heat than the stainless steel.
(d) copper is easier to clean than the stainless steel.

Answer: (c) Copper is a better conductor of heat than the stainless steel.

ch 3 : Fibre to Fabric

                                                              Fibre to Fabric

 

Question: 1 - You must be familiar with the following nursery rhymes

a. ‘Baa baa black sheep have you any wool’.

b. ‘Mary had a little lamb. whose fleece was white as snow’.

Answer the following question.

(a) Which parts of the black sheep have wool?

Answer - The skin of black sheep have wool.

(b) What is meant by the fleece of the lamb?

Answer: Fleece means hair of the lamb.

Question:2 - The silkworm is (a) caterpillar (b) a larva choose the correct option.

(i) a (ii) b (iii) both ‘a’ and ‘b’ (iv) neither ‘a’ nor ‘b’

Answer: (b) both 'a' and 'b'

Question: 3 - Which of the following does not yield wool?

(a)Yak

(b) Camel

(c) Goat

(d) Woolly dog

Answer: (d) Woolly dog

Question: 4 - What is meant by the following terms?

(a) Rearing

(b) Shearing

(c) Sericulture

Answer:

(a) Rearing: Taking care of animals including feeding, grazing, breeding, etc. for meat, and other useful products.

(b) Shearing –The removal of wool from the sheep is called shearing.

(c) Sericulture - The rearing of silkworm for obtaining silk is known as sericulture.

Questions: 5 - Give below is sequence of steps in the processing of steps in the processing of wool which are the missing steps? Add them.

Shearing _________ Sorting _________ _______________.

Answer: Shearing   Scouring  Sorting  Colouring   Spinning

Question: 6 - Make sketches of the two stages in the life history of the silk moth which are directly related to the production of silk.

Answer-

Question:7 - Out of the following which are the two terms related to silk production.silk production.

a. Sericulture

b. Floriculture

c. Moriculture

d. Apiculture and

e. Silviculture

Answer: (a) Sericulture and (b) Moriculture are related to silk production.

Question: 8 - Match the following

 

Ch 2 : Nutrition in Animals

                                                              Nutrition in Animals

 

Q -1 Fill in the blanks.
(a) The main steps of digestion in humans are _____ ____ _____ _____ ______

Answer - The main steps of digestion in humans are Ingestion digestion absorption assimilation egestion

b. The largest gland in human body is _______

Answer- The largest gland in human body is liver.

c. The stomach releases hydrochloric acid and _____ juices which act on food.

Answer- The stomach releases hydrochloric acid and digestive juices which act on food.

d. The inner wall of the small intestine has many finger like structure called _______.

Answer- The inner wall of the small intestine has many finger like structure called villi.

e. Amoeba digest its food in the ________

Answer – Amoeba digest its food in the vacuoles.

Q - 2 - Mark T if the statement is true and F if it is false.
a. Digestion of starch starts in the stomach.

Answer - F

b. The tongue helps in mixing food with sliva.

Answer - T

c. The gall bladder temporarily stores bile.

Answer - T

d. The ruminants bring back swallowed grass into their mouth and chew it for some time .

Answer - T

Q - 3 - Tick (√) mark the correct answer in each of the following.
a. Fat is completely digested in the
(a) Stomach
(b) Mouth
(c) Small intestine
(d) Large intestine

Answer - (c)Small intestine

b. Water from the undigested food is absorbed mainly in the
(a) stomach
(b) food pipe
(c) Small intestine
(d) Large intestine

Answer - (d)Large intestine

Q - 4 - Match the column

Q - 5 - What are villi? What is their location and function.

Answer - Villi is the finger like projections. These are found in the inner walls of small intestine. It helps in absorption of the digested food.

Q- 6 -Where is the bile produced? Which component of the food does it digest?

Answer - Bile is produced in the liver. Bile helps in digestion of fats.

Q -7- Name the type of carbohydrate that can be digested by ruminants but not by humans. Give the reason also.

Answer - Cellulose is the type of carbohydrates which is digested in ruminants but not in humans. Ruminants have a large sac –like structure between the small intestine and large intestine, in which cellulose of the food is digested by the action of certain bacteria. Such structure is not present in human. Hence human cannot digest cellulose while ruminants can.

Q- 8 - Why do we get instant energy from glucose?

Answer - Glucose is simple sugar so there is no need of digestion. It directly reaches the cells where it gives energy after respiration.

Q -9 - Which part of the digestive canal is involved in:
(a) Absorption of food ________
(b) Chewing of food ________
(c) Killing of bacteria ________
(d) Complete digestion of food _______
(e) Formation of faeces _________

Answer -

(a) Small Intestine

(b) Mouth

(c) Stomach

(d) Small Intestine

(e) Large Intestine

Q - 10 - Match the following column

 Q - 11 - Lable the diagram of the digestive system.

Ch 1 : Nutrition in Plants

                                                          Nutrition in Plants 

 

Fill in the blanks:

(a) Green plants are called _       autotrophs __ since they synthesize their own food.

(b) The foods synthesized by the plants are stored as starch .

(c) In photosynthesis solar energy is captured by the pigment called ___ chlorophyll

(d) During photosynthesis plants take in ____CO₂________ and release _ O₂

Name the following:

(i) A parasitic plant with yellow, slender, tubular stem.-------  Cascuta

(ii) A plant that has both autotrophic and heterotrophic mode of nutrition.---------  Insectivorous plants

(iii) The pores through which leaves exchange gases. ------- Stomata

(iv)  A plant that has both autotrophic as well as heterotrophic mode of nutrition. --- Pitcher plant.

(v)  An organism that live is an association of an alga and a fungus   ---------- lichen

(vi)  Amarbel is an example of: ----parasites  

(vii) The plant which traps and feeds on insects is----- pitcher plant

Match the items in column I with those in column II:

Chlorophyll ---–       Leaf.

Nitrogen   –––         Bacteria.

 Amarbel   –––      Parasite.

Animals   –––       Heterotrophs.

Insects  –––       Pitcher Plant

What is Nutrients?

Food is essential for all living organisms. Carbohydrates, proteins, fats, vitamins and minerals are components of food. The chemical substance present in components of food is necessary for our body and is called nutrients.

How humans and animals are are directly or indirectly dependent on plants.

All living organisms require food. Plants can make their food themselves but animals including humans cannot. They get it from plants or animals that eat plants. Thus, humans and animals

are directly or indirectly dependent on plants.

Why do we need food ?

Living organisms need food  to build their bodies, to grow, to repair damaged parts of their bodies and provide the energy to carry out life processes.

What is food ?

Food is the source of energy and every cell of an organism gets energy by the breakdown of glucose. The cells use this energy to carry out vital activities of life.

What is Nutrition?

Nutrition is the sum of all including taking food by an organism and its utilization by the body.

The mode of  nutrition in which organisms make food  themselves from simple substances is

called autotrophic nutrition. Ex plants.

The mode of nutrition in which organisms take in ready made food prepared by the plants

called heterotrophic nutrition. Ex animals

Whether food is made in all parts of a plant or only in certain parts?

Only certain part plant like leaves having green pigment chlorophyll. so Leaves are called  the food factories of plants.

Besides leaves, photosynthesis also takes place in other green parts of the plant — in green stems and green branches. The desert plants have scale- or spine-like leaves to reduce loss of water by transpiration. These plants have green stems which carry out photosynthesis.

How do plants obtain the raw materials from the surroundings?

Water and minerals present in the soil are absorbed by the roots and transported to the leaves.

Carbon dioxide from air is taken in through the tiny pores present on the surface of the leaves. Such pores are called stomata. These pores are surrounded by ‘guard cells’

How do the raw materials transport them to the food factories of the plants?

Plants have pipe-like vessels to transport water and nutrients from the soil. The vessels are

made of special cells, forming the vascular tissue. The vascular tissue for the transport of water and nutrients in the plant is called the xylem. The vascular tissue for the transport of water and nutrients in the plant is called the xylem. Thus, xylem and phloem transport substances in plants

What is cell ?

The bodies of living organisms are made of tiny units called cells therefore Cell are called the building blocks of living organism.

Cells can be seen only under the microscope. Some organisms are made of only one cell. They are called Unicellular Ex. Amoeba, Paramecium etc

Living organism made up of many cells are called Multi cellular like man, tree etc

What is the cell membrane?

The cell is enclosed by a thin outer boundary, called the cell membrane Most cells have a distinct, centrally located spherical structure called the nucleus  The nucleus is surrounded by a jelly-like substance called cytoplasm.

What is tissue ?

A tissue is a group of cells that perform specialized function in an organism. For example, the vascular tissue for the transport of water and nutrients in the plant is called the xylem.

What are the main requirements of photo synthesis?

Chlorophyll, sunlight, carbon dioxide and water are necessary to carry out the process of

Photosynthesis.

Explain the process of Photosynthesis?

Carbon dioxide from air is taken in through stomata. chlorophyll helps leaves to capture the energy of the sunlight. This energy is used to synthesize (prepare) food from carbon dioxide and water. Since the synthesis of food occurs in the presence of sunlight, it is called photosynthesis

Carbon dioxide +  water ---------sunlight/chlorophyll--àCarbohydrate  +    oxygen

Here the carbohydrates ultimately get converted into starch

How would you test the presence of starch on leaves?

Put 2-3 drops of dilute iodine solution on the leaves. Appearance of a blue-black colour indicates presence of starch in the leaves.

Why are leaves called the food factories of plants? Explain.

Leaves are called the food factories of plants due to following functions

ü  Green leaves have all the raw materials neccessary to carry the process of photosynthesis. 

ü  They have chlorophyll (green pigment) which captures the energy of sunlight. 

ü  Leaves consist of tiny pores called stomata on their surface. 

ü  Carbon dioxide from air is taken in through stomata. 

ü  Water and minerals are absorbed by the roots from the soil and transported to the leaves by vessels.

ü   

    Why sun is called the ultimate source of energy for all living organisms?

The solar energy is captured by the leaves and stored in the plant in the form of food. and this in turn use by other organism to get food to obtain energy Thus, sun is the ultimate source of energy for all living organisms.

Why algae are green in colour?

Algae contain chlorophyll which gives them the green colour. It can also prepare their own food by photosynthesis.

What are the main components presents in carbohydrates?

The main components presents in carbohydrates are carbon, hydrogen and oxygen.

From where do the plants obtain nitrogen?

Soil has certain bacteria  that convert gaseous nitrogen into a usable form and release it into the soil. These soluble forms are absorbed by the plants along with water.

By adding fertilizers rich in nitrogen to the soil farmers also made nitrogen available for plants

What is parasitic nutrition?

The mode of by which parasitic organism get and synthesize their food is called parasitic nutrition. Example Cucuta It does not have chlorophyll It takes readymade food from the plant

on which it is climbing. The plant on which it climbs is called a host.

How Pitcher plants get their nutrition?

There are a few plants which can trap insects and digest them. Such plants may be green or of some other colour. Such insect-eating plants are called insectivorous plants.

Example Pitcher plant

When an insect lands in the pitcher, the lid closes and the trapped insect gets entangled into the hair. The insect is digested by the digestive juices secreted in the pitcher.

Why does the pitcher plant feed on insects though it is green? 

The pitcher plant does not get all the required nutrients especially those of nitrogen from the soil, hence it feeds on insects.

What is saprotrophic nutrition? What is the mode of nutrition in fungi?

This mode of nutrition in which organisms take in nutrients in solution form from dead and decaying matter is called saprotrophic nutrition. Plants which use saprotrophic mode of

nutrition are called saprotrophs. Example Fungi that secrete digestive juices on the dead

and decaying matter and convert it into a solution. Then they absorb the nutrients from it.

How do fungi appear suddenly during the rainy season?

Air generally consists of fungal spores. When these spores come in contact with warm things they germinate and grow. During rainy season, there are more chances of things getting wet.
Hence, fungi appear more in rainy season.

What do you under stand by symbiotic relationship present in some organism?

Some organisms live together and share shelter and nutrients. This is called symbiotic relationship . E.g. an alga, and a fungus live together fungus provides shelter, water and

Minerals to the alga and, in return, the alga provides food which it prepares by photosynthesis.

What is Symbiosis?

Symbiosis - It is the type of nutrition in which two different kinds of depend on each other for their nutrition. In this both the organisms are benefitted by each other e.g., lichen. In this one alga and one fungus live together and remain in symbiotic relationship.

How nutrients are replenished in soil?

Nutrients are replenished in soil by following ways

1.By  spreading manure or fertilizers that contain nutrients such as nitrogen in the fields

2.By  The bacterium Rhizobium that can take atmospheric nitrogen and convert it into a soluble form.

How do leguminous plants help replenishing soil fertility?

Rhizobium cannot make its own food. So it lives in the roots of gram, peas, moong beans

and other legumes and provides them with nitrogen. In return, the plants provide food and

shelter to the bacteria

Distinguish between a parasite and a saprotrophs

Parasite

1. A parasite takes readymade food from the organism on which it feeds.

2. They feed on a living organism.

3. The organism on which it feeds is called host.

4. It deprives the host of valuable nutrients.

saprotrophs

1. They secrete the digestive juices on the matter they live and convert it into a solution and then absorb it.

2. They feed on dead and decaying organism.

3. They do not feed on a living organism.

4. There is no host at all.

Why algae are green in colour?

Algae are green in colour as they contain chlorophyll which gives them the green colour. Algae can also prepare their own food by photosynthesis. Slimy, green patches in ponds or in other stagnant water  bodies are algae.