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Class- VII-CBSE-Science, , Forest Our Lifeline, , CBSE NCERT Solutions for Class 7 Science Chapter 17, Back of Chapter Questions, 1., , Explain how animals dwelling in the forest help it grow and regenerate., Solution:, In the forests, animals help in dispersing the seeds of certain plants. The nutrients, present in the decaying animal dung allows the growth of the various type of, seedlings, and this is how animals dwelling in the forest help it to grow and, regenerate., , 2., , Explain how forests prevent floods., Solution:, Forest acts as a natural absorber of rainwater. In the absence of trees, the rainwater, would hit the ground directly resulting in a flood. Heavy rain may also damage the, soil. However, because of the presence of trees, rainwater hits the ground slowly, and not directly, and the roots of trees bind the soil together. Hence, before, flooding, all the rain seeps through the field and prevent soil erosion. In this way,, forests prevent floods., , 3., , What are decomposers? Name any two of them. What do they do in the forest?, Solution:, Decomposers are the micro-organisms that convert the dead animals and plants into, useful humus. Example of decomposers is Mushroom and bacteria. The, decomposers continuously maintain the nutrient supply to the growing plants in a, forest., , 4., , Explain the role of forest in maintaining the balance between oxygen and carbon, dioxide in the atmosphere., Solution:, Forests are known as green lungs since the plants present in forest produce oxygen, and remove carbon dioxide in the air through the process of photosynthesis and, thus help in respiration in animals. This way, forests help in maintaining a balance, of oxygen and carbon dioxide in the atmosphere., , 5., , Explain why there is no waste in a forest., Solution:, Wastes produced in forests are usually the dead animals and decaying plant parts., Animals such as vultures, crows, jackals and insects feed upon dead animals., Decomposers convert various dead organisms such as plants and animals, to form, humus that is recycled into the soil. So, there is no waste in the forest., , Practice more on Forest Our Lifeline, , Page - 1, , www.embibe.com
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Class- VII-CBSE-Science, , 6., , Forest Our Lifeline, , List five products we get from forests?, Solution:, Products that we get from forests includes:, , 7., , (i), , Wood, , (ii), , Honey, , (iii), , Medicine, , (iv), , Oil, , (v), , Gum, , Fill in the blanks:, (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 ________., , Solution:, , 8., , (a), , pollination, , (b), , air and water, , (c), , lowest, , (d), , soil, , Why should we worry about the conditions and issues related to forests far from, us?, Solution:, There are various reasons for which we should be vigilant about matters related to, forests., , 9., , (i), , The decrease in the area of forest leads to increased carbon dioxide in the, air, which leads to an increase in temperature of the earth., , (ii), , Absence of trees results in soil erosion., , (iii), , Floods become more frequent in the absence of forest., , (iv), , Forests are shelter to animals as well as a source of food. The habitat of, animals is adversely affected when the forests are destroyed. Therefore, we, need to conserve our forests., , Explain why there is a need of variety of animals and plants in a forest., , Practice more on Forest Our Lifeline, , Page - 2, , www.embibe.com
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Class- VII-CBSE-Science, , Forest Our Lifeline, , Solution:, A variety of plants and animals is needed to a greater extent to help the forest in, regeneration and growth. Variety in plants helps herbivores by providing more food, and habitat, which increases the source of food for carnivores, which are herbivores., The microorganisms that act as decomposers help in the maintenance of a supply, of nutrients into the soil and growth of plants. All these help in the overall, development of the forest., 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., , Solution:, , 11., , Which of the following is not a forest product?, , Practice more on Forest Our Lifeline, , Page - 3, , www.embibe.com
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Class- VII-CBSE-Science, , (i), , Gum, , (ii), , Plywood, , (iii), , Sealing wax, , (iv), , Kerosene, , Forest Our Lifeline, , Solution:, (iv), 12., , Kerosene, , 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., , Solution:, (ii), 13., , Plants and animals in a forest are not dependent on one another., , Micro-organisms act upon the dead plants to produce, (i), , sand, , (ii), , mushrooms, , (iii), , humus, , (iv), , wood, , Solution:, (iii), , humus, ⧫⧫⧫, , Practice more on Forest Our Lifeline, , Page - 4, , www.embibe.com
