NCERT Solutions for class 7 Science Chapter-17

Chapter – 17 Forests: Our Lifeline

Chapter Exercise

Page no. – (217)

Q.1– Explain how animals dwelling in the forest help it grow and regenerate.

Ans.1– In the followings ways, Animals dwelling in the forest help it grow and regenerate:-

The microorganism Covert the dead animals and plant into the humus.
Animals help in pollination which helps in growing much numbers of plants.
Animal dung can convert into manure for the seed and the seedlings grow to plant.

Q.2– Explain how forests prevent floods.

Ans.2– The forest can absorb lot of water at the rainfall and allows it to seep. That’s why forest prevent floods.

Q.3– What are decomposers? Name any two of them. What do they do in the forest?

Ans.3– The Microorganism Covert the dead animals and plant into the humus is called decomposers.

Ex. bacteria and fungi.

Q.4– Explain the role of forest in maintaining the balance between oxygen and carbon dioxide in atmosphere.

Ans.4– As we know, plants release oxygen and inhale carbon dioxide. In the same way, humans and animals release carbon dioxide to continue their life and get oxygen. Thus, the forest has an important role in maintaining the balance between oxygen and carbon dioxide in the atmosphere.

Q.5– Explain why there is no waste in a forest.

Ans.5– There is no waste in a forest because everything recycled in a forest and decomposers convert all dead plants and bodies into humus.

Q.6– List five products we get from forest?

Ans.6– The followings are the five products list, we get from forest:-

Wood.
Paper
Fruits and vegetable.
Medicine
Spices

Q.7– Fill in the blanks;

The insects, butterflies, honeybees and birds help flowering plants in ____.
A forest is a purifier of ____ and ____.
Herbs from the ____ layer in the forest.
The decaying leaves and animal droppings in a forest enrich the ____.

Ans.7–

The insects, butterflies, honeybees and birds help flowering plants in __pollination__.
A forest is a purifier of __air__ and __water__.
Herbs from the __lowest__ layer in the forest.
The decaying leaves and animal droppings in a forest enrich the __soil__.

Q.8– Why should we worry about the condition and issues related to forests far from us?

Ans.8– Forest is very important for us and they provide various items, greenery, clean air shelter for animals, play a vital role in water cycle etc. and we should worry about the forest for the following reasons.

Deforestation,
Soil erosion,
Global warming,
Desertification etc.

Q.9– Explain why there is a need of variety of animals and plants in a forest.

Ans.9– The variety of animals and plants in a forest is a very important because the varieties of animals are necessary for their survival and maintenance of food chain.

Food chain:-

Plants > grasshopper > mice > snacks > eagle > plants.

Every food chain link with each. If any food chain disturbed, so it is effect on other food chains.

Q.10– In fig. 17.15 the artist has forgotten to put the labels and directions on the arrows. Mark the directions on the arrows and label the diagram using the following labels: clouds, rain, atmosphere, carbon dioxide, oxygen, plants, animals, soil, roots, water table.