Here in this post we provided NCERT Exemplar Problem Class 7 Science Forests : Our Lifeline Chapter 17 Full Explanation by group of Science Experts. We have provided here each questions answer with reason behind the answer.
Hope it help you!
Forests : Our Lifeline Class 7 Exemplar full Explanation:
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Multiple Choice Questions
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:- b) Forests
Forests serves as green lungs, it gives larger amount of oxygen and take in great amount of carbon dioxide.
2) Boojho visited a forest near his town with 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:- c) Both birds and animals
Forests are home of both birds and animals.
3) Which among the following forest Animals is the smallest?
a) Fox
b) Boar
c) Bison
d) Porcupine
Answer:- d) porcupine
Porcupine is the smallest forest Animal.
4) Which of the following has the strongest stem?
a) A tree
b) A creeper
c) A climber
d) A bush
Answer:-d) A bush
Bush has the strongest stem among the above.
5) Which of the following is not prepared form the wood obtained from forest?
a) Paper
b) Thermocol
c) Matchsticks
d) Plywood
Answer:- b) thermocol
Thermocol is not made up of wood obtained from Forests. It is polymer .
6) Which of the following is not the name of a tree?
a) Teak
b) Sal
c) Porcupine
d) Kachnar
Answer:- c) porcupine
Porcupine is the name of animal.
7) Pick the options 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:- a) semal, hornbill
Semal is tree and hornbill is animal respectively.
8) Which of the products is not obtained from a forest?
a) Honey
b) Catechu
c) Gum
d) Ginger
Answer:-d) Ginger
Ginger is obtained in the farms and kitchen gardens. Not in forest.
9) The branchy part of a tree above the stem is known as
a) Crown
b) Canopy
c) Sapling
d) Humus
Answer:-a) crown
Branchy part of tree above the stem is known as crown.
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:- c) creating flood conditions.
Forests are not responsible for creating flood conditions. Flood is the natural disaster which occurs due to heavy rainfall. But deforestation may lead to flood conditions.
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Very Short Answer Questions
11) 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:- forest is a dense area of trees . Many big trees present over there on the larger area. In These dense part of trees noise is get absorbed . Therefore if there is no noise pollution in the forest . the sound of nearby heavy vehicles from the highway also get absorbed as noise does not pass from the dense part of trees.
12) State whether the following statements are true or false . If false , give the correct statement.
a) Forests influence climate, water cycle and air quality.
Answer:- True.
b) In a forest, trees form the uppermost layer, followed by herbs. The shrubs from the lowest layer of vegetation.
Answer:- False.
In the forest trees from the uppermost layer is trees followed by the shrubs . The herbs from the lowest layer of vegetation.
c) The forest keeps on growing and changing and can regenerate.
Answer:- True
d) Forests protect the soil from erosion.
Answer:- True
13) 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:-
The correct food chain is –
Grass → insects → frog → snake → eagle.
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Short Answer Questions
14) Give names of any four birds which you expect to see in a forest.
Answer:- many birds and animals lives in the forest. Among them name of some birds which we expect to see in the forest are –
Kingfisher , maina (myna), koel, jungle crow, hornbill.
15) 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. India’s climate and type of soil , weather pattern changes from place to place. Climatic conditions of the two different forest may be different. These different climatic conditions leads to the variations in the animals and plants which live over there. We see somewhere the climate is too hot or too cold. According to that climatic conditions animals and plants adapt themselves to survive over there . Thus there is difference between two forest over two different place. Therefore they both would not have seen same type of plants and animals in the forests.
16) “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:- Many animals living in the forest eat the fruits of the trees which seeds are not digested by the animals and thus they excrete it. Seeds has a tough coat over it thus it does not get damage. The dead plant and Animals tissue are decomposed after some time into a dark coloured substances known as humus.
This humus is very much useful for the plants to grow . Plants get nutrients from the humus. Some micro organisms convert the dead plants and dead animals into humus which are known as decomposers. Thus the nutrients from the humus is absorbed by the roots of plants. Thus the bunch of seedlings were seen sprouting on a heap of Animals dropping in a forest.
17) Match Column I with Column II
Column I | Column II |
a) Decomposers | i) Dead plant and animal tissues |
b) Canopy | ii) Habitats for wild life |
c) Porcupine | iii) Micro-organisms |
d) Humus | iv) Wild animals |
e) Forest | v) Branches of tall trees |
a) Decomposers → iii) micro- organisms
b) Canopy → v) branches of tail Trees
c) Porcupine → iv) wild animals
d) Humus → i)dead plant and Animal tissues
e) Forest→ ii) habitats for wild Life
18) Deforestation may lead to floods , why?
Answer:- plants or trees plays an important role in the natural disaster flood.
Roots of plants and big trees bind the soil particles with them and thus stops the soil erosion. Also binding of roots to the soil does not allow the soil to flow with the water of heavy rainfall which also stops the soil erosion. Every plant needs water as nutrients. They absorb water also Store the water inside the ground level. Which may further used by the plants . Where there are plants there is water inside the soil. Thus they may absorb large amount of water at the time of rainfall which also can prevent the flood.
If there are no plants or deforestation occur, it is true that heavy rainfall may lead to floods. As there will be no absorption of water and water will not be hold by roots thus leads to flood.
19) Name any four useful products other than wood, which we get from forests?
Answer:- Any four useful products rather than wood found in the forest are –
Spices , medicinal plants, gum , fodder for animals , oils.
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Long Answer Questions
(20) 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:-
On the basis of given picture the activities which are going on inside the forest –
A) Forests are large source of oxygen . They gives large amount of oxygen into the environment which is used by the human beings and animals.
B) The carbon dioxide in the atmosphere which is also expelled by the human beings and animals is used by the plants for the process of photosynthesis. Formation of their food.
C) Forests gives out so much important things for human beings day to day life.
D) For the nutrients of the plants decomposers play an important role.
E) Forests gives the place for animals and birds shelter.
21) People say that nothing goes waste in a forest. Can you explain , how?
Answer:-
A) Plants in the forest are totally useful. Which almost every part is useful by the human beings.
B) It provides shelter to the animals.
C) The dry leaves over there is decomposed into Dark coloured humus which is further used as nutrients to the plants .
D) The animals dead over there are decomposed after some time which becomes food of vultures, crows, and decomposers.
E) Dead plants Wood or broken branches are used as firewood.
Therefore nothing goes waste in the forest.
22) Give any four factors which are responsible for the destruction of forests.
Answer:- Now a days, deforestation is occurring on a large scale. Which not at all good for human beings. But due to industrial development all over the world forest are cutting down for the maximum place should be obtained. Construction of roads leading to the deforestation. As well as construction of buildings and homes for the larger place should obtained for locality. There is a huge demand of place for the increasing population therefore by destruction of forests we get place. Also we get large amount of wood from forest trees which is used by humans for the furniture also for firewood.
23) Draw a figure showing two animals, two birds and a few trees as a part of a forest.
Answer:-
24) All the needs of animals living in a forest are fulfilled. Justify this statement in a few sentences.
Answer:- All the needs of Animals living in a forest are fulfilled is the true statement. Because forest provide shelter to the animals a place for living. Forests provide food to the animals living over there . As many trees grows in the forest also grow fruits used by Animals. Ponds and small lakes in forest provide water to the animals living there. Thus the given statement is true.
25) “Forests are our lifeline.” Write five sentences on this topic.
Answer:- “forest are our lifeline” is the true line . Forests provide us many important things which is useful in day to day life . Large amount of trees in the forest provide oxygen which increases the amount of oxygen in the atmosphere. Also they take in carbon dioxide from the atmosphere for preparation of their food. Carbon dioxide is responsible for the climatic change also increases the temperature of the earth causing green house effect. Forests provide wood, medical plants , gum any thing which we need. They give shelter to the animals. Forests prevent soil from erosion. They prevent flood. They help in maintaining the water level under the soil by abortion of water by the roots. There are many things which are almost good about the forest. Thus forest is our lifeline is true.