Page No 218: - Chapter 17 Forests Our Lifeline class 7 ncert solutions Science - SaraNextGen [2024-2025]

Updated By SaraNextGen

On April 24, 2024, 11:35 AM

Question 7:

Fill in the blank:

(a) The insects, butterflies, honeybees and birds help flowering plants in _______.

(b) A forest is a purifier of _______ and ________.

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

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

Answer:

(a) The insects, butterflies, honeybees and birds help flowering plants in __pollination__.

(b) A forest is a purifier of __air__ and __water__.

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

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

Question 8:

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

Answer:

There are various reasons for which we should be vigilant about matters related to forests.

(i) A decrease in forest area would lead to an increase in carbon dioxide in air. This will lead to an increase of earth’s temperature.

(ii) Soil erosion would occur if there are no forests.

(iii) Floods would be more frequent in absence of forests.

(iv) Forests provide shelter and food to animals. When forests are adversely affected, the habitats of wild animals are also adversely affected.

Therefore, we need to conserve our forests.

Question 9:

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

Answer:

A greater variety of plants and animals in the forests helps it to regenerate and grow. Greater variety of plants means more food and habitat for the herbivores. An increase in herbivores means more food for carnivores. Decomposers help to maintain the supply of nutrients to the soil and to the growing plants. This wide variety makes forest a dynamic living entity.

Question 10:

In figure, 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

Answer:

Question 11:

Which of the following is not a forest product?

(i) Gum

(ii) Plywood

(iii) Sealing wax

(iv) Kerosene

Answer:

(iv)Kerosene

Question 12:

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.