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

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Question 20:

Figure shows a part of a forest.

As showing in images is a part of a forest.

Part of a Forest.

As showing in images is a part of a forest.

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

Answer:

  1. Oxygen is given out by plant leaves.

  2. Carbon dioxide is consumed by the plants to prepare their food by the process of photosynthesis.

  3. Decomposers play an important role in providing nutrients to plants.

Question 21:

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

Answer:

  1. Dry leaves and remains of dead animals are converted to a dark csoloured substance called humus. This provides nutrients to the plants.

  2. Dead animals become food for vultures, crows, jackals and insects.

  3. Broken branches of trees are used as fuel by the people living in the vicinity of the forest.

Question 22:

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

Answer:

  1. Construction of roads

  2. Construction of buildings

  3. Industrial development

  4. Increasing demand of wood

Question 23:

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

Answer:

Image showing two animals and a few trees

Image Showing Two Animals and a Few Trees

Image showing two animals and a few trees

Question 24:

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

Answer:

Forest provide home, food and water to the animals living there. There are a large number of various types of animals in the forest. The forest provide a natural habitat to animals. The different layers of regulation present in a forest provide food and shelter. Forest provide leaves, flowers, fruits, seeds, nuts and bark of trees as food for herbivorous animals. The carnivorous animals hunt and eat herbivorous animals. The dense bushes, tall grasses and thick trees provide shelter and also protection for herbivorous animals.

Question 25:

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

Answer:

  1. Forests give oxygen to keep us alive.

  2. Forests absorb carbon dioxide, a gas which in excess in atmosphere contribute to climatic changes.

  3. Forests provide us wood, gum, medicinal plants and many more things.

  4. Forests save the soil from erosion.

  5. Forests help in maintaining the ground water level.

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