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Forests : Our Lifeline

Class 7th Science NCERT Exemplar Solution
Multiple Choice Questions
  1. Which of the following serve as green lungs?A. Green pigment of the plants B. Forests C.…
  2. Boojho visited a forest near his town with his classmates and his teacher. As they were…
  3. Which among the following forest animals is the smallest?A. Fox B. Boar C. Bison D.…
  4. Which of the following has the strongest stem?A. A tree B. A creeper C. A climber D. A…
  5. Which of the following is not prepared from the wood obtained from forest?A. Paper B.…
  6. Which of the following is not the name of a tree?A. Teak B. Sal C. Porcupine D. Kachnar…
  7. Pick the option which gives the names of a tree and an animal, respectively from the…
  8. Which of the products is not obtained from a forest?A. Honey B. Catechu C. Gum D. Ginger…
  9. The branchy part of a tree above the stem is known asA. crown B. canopy C. sapling D.…
  10. Forests are not responsible forA. providing medicinal plants. B. maintaining the flow of…
Very Short Answer Questions
  1. Paheli while moving in a forest observed that there was no noise pollution, though lots of…
  2. State whether the following statements are true or false. If false, give the correct…
  3. Paheli wrote a food chain in the following way: frog →eagle → insects → grass → snake The…
Short Answer Questions
  1. Give names of any four birds which you expect to see in a forest.…
  2. Two friends shared their experiences of their vacation trip to two different forests. Do…
  3. “A bunch of seedlings were seen sprouting on a heap of animal dropping in a forest.” How…
  4. Match Column I with Column II
  5. Deforestation may lead to floods. Why?
  6. Name any four useful products other than wood, which we get from forests.…
Long Answer Questions
  1. Figure 17.1 shows a part of a forest. Write any three activities going on in the forest on…
  2. People say that nothing goes waste in a forest. Can you explain, how?…
  3. Give any four factors which are responsible for the destruction of forests.…
  4. Draw a figure showing two animals, two birds and a few trees as a part of a forest.…
  5. All the needs of animals living in a forest are fulfilled. Justify this statement in a few…
  6. “Forests are our lifeline.” Write five sentences on this topic.

Multiple Choice Questions
Question 1.

Which of the following serve as green lungs?
A. Green pigment of the plants

B. Forests

C. Kitchen gardens

D. Green house gases


Answer:

Reason- Forests serve as green lungs because they release oxygen, which is used by us for respiration.


Question 2.

Boojho visited a forest near his town with his classmates and his teacher. As they were entering the forest, their class teacher told them not to make noise in the forest as noise could disturb the
A. birds

B. animals

C. both birds and animals

D. plants


Answer:

Reason- Because the birds and animals make noises to alert other animals in the forests.


Question 3.

Which among the following forest animals is the smallest?
A. Fox

B. Boar

C. Bison

D. Porcupine


Answer:

Reason- Fox, Boar and Bison are comparatively larger in size than porcupine.

This is a picture of porcupine.



Question 4.

Which of the following has the strongest stem?
A. A tree

B. A creeper

C. A climber

D. A bush


Answer:

Reason- A tree has the most thick and strongest stem in comparison to a creeper, a climber and a bush.


Question 5.

Which of the following is not prepared from the wood obtained from forest?
A. Paper

B. Thermocol

C. Matchsticks

D. Plywood


Answer:

Reason- Thermocol is prepared from plastic.


Question 6.

Which of the following is not the name of a tree?
A. Teak

B. Sal

C. Porcupine

D. Kachnar


Answer:

Reason- Porcupine is the name of a forest animal.


Question 7.

Pick the option which gives the names of a tree and an animal, respectively from the following.
A. semal, hornbill

B. sal, khair

C. chinkara, blue bull

D. neem, palash


Answer:

Reason- Semal is a plant and Hornbill is a bird (animal). Sal and khair is both tree. Chinkara and blue bull are both animals. Neem and palash are both trees.

This is a picture of semal tree. This is a picture showing


Hornbill bird.



Question 8.

Which of the products is not obtained from a forest?
A. Honey

B. Catechu

C. Gum

D. Ginger


Answer:

Reason- Ginger is actually a type of a root, rhizome.

This is a photograph showing ginger as a type of root.



Question 9.

The branchy part of a tree above the stem is known as
A. crown

B. canopy

C. sapling

D. humus


Answer:

Reason- Canopy is the arrangement when branch of one tree fells over the other tree. Sapling is the earliest stage of plant growth, short in height. Dead plants and plants and animal tissue is converted into a dark coloured substance called humus by the micro-organisms.


Question 10.

Forests are not responsible for
A. providing medicinal plants.

B. maintaining the flow of water into the streams.

C. creating flood conditions.

D. absorbing rainwater and maintaining water table.


Answer:

Reason- Trees help in getting rid of flood as they absorb all the rainwater.



Very Short Answer Questions
Question 1.

Paheli while moving in a forest observed that there was no noise pollution, though lots of heavy vehicles were passing from the nearby highway. Explain why?


Answer:

This is because the noise from the vehicles is absorbed by the trees. This is how the trees help in overcoming the noise pollution.



Question 2.

State whether the following statements are true or false. If false, give the correct statement.

(a) Forests influence climate, water cycle and air quality.

(b) In a forest, trees form the uppermost layer, followed by herbs. The shrubs form the lowest layer of vegetation.

(c) The forest keeps on growing and changing and can regenerate.

(d) Forests protect the soil from erosion.


Answer:

(a) True

Reason- Forests keep a check on climate, water cycle and air quality. Forests maintain the climate and water cycle through rain and air quality by maintaining the carbon dioxide and oxygen level in the environment.


(b) False.


In a forest, trees form the uppermost layer, followed by shrubs. The herbs form the lowest layer of vegetation.


Reason- Herbs are smaller than shrubs.


This is a picture showing difference in the height of herbs, shrubs and trees.



(c) True


Reason- The forest keeps on changing as the climate conditions changes. New plants are grown by the seed dispersed by animals or air.


(d) True


Reason- The forest helps in prevention of soil erosion as the roots bind to the soil and hence does not allow the removal of the top layer of soil.



Question 3.

Paheli wrote a food chain in the following way:

frog →eagle → insects → grass → snake

The chain is not in the correct order. Help her to write the food chain correctly.


Answer:

Grass → insects → frog → snake → eagle.




Short Answer Questions
Question 1.

Give names of any four birds which you expect to see in a forest.


Answer:

Owl, woodpecker, Eagle, Peacock are the birds that we can expect to see in a forest.



Question 2.

Two friends shared their experiences of their vacation trip to two different forests. Do you think they would have seen the same type of plants and animals during their respective trips? Give reason.


Answer:

No, they would have not seen the same type of plants and animals during their respective trips because different climatic conditions give rise to different plants. Animals are habited to environment conditions that suit them. For example- A camel is only found in the desert.

But if two forests are not very far from each other than the plant species may have been same.



Question 3.

“A bunch of seedlings were seen sprouting on a heap of animal dropping in a forest.” How do you think is the seedling benefited from the animal dung?


Answer:

The animal dung provides nutrients to the seedlings. The essential nutrients required for the growth of plant is readily absorbed from the animal dung. Animal dung is rich in elements like nitrogen.



Question 4.

Match Column I with Column II



Answer:

(a) Decomposers- (iii) micro-organisms

Reason- Micro- organisms are known as decomposers because they decompose on the dead and decay matter.


(b) Canopy- (v) branches of tall trees


Reason- Branches of tall tree over the other tree is known as canopy.


(c) Porcupine- (iv) wild animal


Reason- Porcupine is a wild animal found in the forests


(d)Humus- (i) dead plants and animal tissue


Reason- Dead plants and animal tissue is decomposed by the micro-organism into a dark- coloured substance called as Humus.


(e) Forest- Habitats for wild life


Reason- Forest is a home for wild animals as well as trees



Question 5.

Deforestation may lead to floods. Why?


Answer:

Continuous cutting of trees is known as deforestation. The roots of the trees help in binding the soil together. Trees absorb the rainwater and allow it to enter the soil, thus maintaining the water table also. In the absence of tree, rainwater leads to flood. And, as no trees are present, therefore, they easily remove the top layer of the soil causing soil erosion.



Question 6.

Name any four useful products other than wood, which we get from forests.


Answer:

four useful products which we get from forests are:

1. Gums


2. Oils


3. Matchsticks


4. Medicinal plants




Long Answer Questions
Question 1.

Figure 17.1 shows a part of a forest.



Write any three activities going on in the forest on the basis of this figure.


Answer:

Three activities going on in the forest are:

1. Carbon dioxide in the air is used by the absorbed by the trees.


2. Oxygen is being released by the trees in the air, which is used by the animals for respiration.


3. Decomposers act on the dead plant and animal tissues and convert it into rich humus content.



Question 2.

People say that nothing goes waste in a forest. Can you explain, how?


Answer:

The dead plants and animal tissue is converted into humus, a black coloured substance, by the micro-organism. This humus is rich in the nutrients. The humus ensures that it gets readily mixed with the soil, so that it could be absorbed by the roots of the plants. The dead animals are eaten by the eagles, hawks and vultures.

That is why, it is said that nothing goes waste in a forest.



Question 3.

Give any four factors which are responsible for the destruction of forests.


Answer:

Four factors which are responsible for the destruction of forests are:

1. For agricultural purposes.


2. For the construction of roads and buildings.


3. To make items such as paper, plywood, etc.


4. To make factories or companies at the place of forests



Question 4.

Draw a figure showing two animals, two birds and a few trees as a part of a forest.


Answer:




Question 5.

All the needs of animals living in a forest are fulfilled. Justify this statement in a few sentences.


Answer:

1. Forests provide animals with food to eat.

2. Forests provide animals with water to drink.


3. Forest serve as a home to a large number of animals, thus providing them with shelter.


All the basic needs of the animal living is fulfilled by the forest.



Question 6.

“Forests are our lifeline.” Write five sentences on this topic.


Answer:

1. They provide us with oxygen to breathe.

2. They provide us with food to eat.


3. They provide us with wood to make paper, matchsticks, etc.


4. They provide us with medicinal plants.


5. They provide us with gums, oils and spices.