NCERT Class VII Science Solutions: Chapter 17-Forests: Our Lifeline Part 4

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Question 7:

Fill in the blank:

  1. The insects, butterflies, honeybees and birds help flowering plants in _____________.

  2. A forest is a purifier of _____________ and _____________.

  3. Herbs form the _____________ layer in the forest.

  4. The decaying leaves and animal droppings in a forest enrich the _____________.

Answer:

  1. The insects, butterflies, honeybees and birds help flowering plants in pollination.

  2. A forest is a purifier of air and water.

  3. Herbs form the lowest layer in the forest.

  4. 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:

Forests are very important resources. We should be careful and concerned about the issues related to forest due to following reasons:

  • If there are no forests, there would be more floods and more soil erosion.

  • 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.

  • Forests are the dwelling of many animals. Deforestation will endanger our life and environment.

  • In the absence of trees and plants, the animals will not get food and shelter.

  • Forests provide us large number of useful products including wood, fruits and medicines. These products would not be available in the absence of trees and plants.

Question 9:

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

Answer:

Variety of animals and plants living in forests build a rich biodiversity. 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. This biodiversity make forests more productive, stable and resilient. If there is no grass, all herbivores would die. If there are no carnivores, all herbivores would eat up all the plants and there is shortage of food. If there are no decomposers, the dead remains of plants and animals would pollute the environment. Due to such biodiversity a balance in nature is maintained.

Question 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, and water table.

As showing in images is a result for water table

Water Cycle Unlabelled

Answer:

As showing in images is a result for water table

Water Cycle Labelled

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