Question 1. Explain how animals dwelling in the forest help it grow and regenerate.
Solution 1.
Animals dwelling in the forest help it grow and regenerate in the following ways
- Animals help in dispersal of seeds.
- Decaying dung of animals provides nutrients for plants to grow
- Microorganisms prepare humus from dead plants and animals.
Question 2. Explain how forests prevent floods.
Solution 2. Plants in the forest hold water and do not allow the rainwater to fall directly on earth in this way forests prevent floods.
Question 3. What are decomposers? Name any two of them. What do they do in the forest?
Solution 3. Decomposers are micro-organisms that convert dead animals and plants into humus. Examples of decomposers are bacteria and fungi. They replenish the nutrients back to the soil of the forest by cleaning up and converting up the dead and decaying plants and animals of the forest.
Question 4. Explain the role of forests in maintaining the balance between oxygen and carbon dioxide in the atmosphere.
Solution 4. Plants in the forest release oxygen in large amount during the process of photosynthesis this oxygen is inhaled by animals present in the forest and release carbon dioxide and then again plant use this carbon dioxide for respiration this is how a forest maintain the balance between oxygen and carbon dioxide. Since there is a large number of plants in the forest, the forest contributes to maintaining the balance of this cycle in nature.
Question 5. Explain why there is no waste in a forest.
Solution 5. In forests, almost each and every waste material is biodegradable and they are converted into humus. Hence, there is no waste in a forest.
Question 6. List five products we get from forests.
Solution 6.
i) Medicines
ii) Spices
iii) Wood
iv) Paper
v) Gum
Question 7. 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:
(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?
Solution 8.
We should worry about the conditions and issues related to forests far from us for the following reasons:
- Forests maintain the balance of carbon dioxide and oxygen in nature and the reduction in forests would result in an increment of carbon dioxide in nature which is very harmful to all living beings and can cause global warming.
- Plants in the forest hold the soil and the depletion of forests would result in soil erosion.
- A decrease in the forest would adversely affect the lives of animals that are living in the forest because the forest is the home of many wild animals and they will be homeless because of the decrease in the forest.
- Plants in the forest hold the water and hence because of the absence of forests flooding there will be more often.
- The reduction of forest land will lead to desertification.
Question 9. Explain why there is a need for a variety of animals and plants in a forest.
Solution 9.
A variety of plants and animals in the forests supports plants to regenerate and grow well as this variety maintains the food chain in the forest. A more excellent range of plants serves food to herbivores, which in turn serve as the food for carnivores such as lions, tigers etc. Decomposers turn dead and decaying animals and plants into humus; thereby they maintain the recycling of nutrients. This wide variety of plants and animals makes a forest a dynamic living entity.
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, water table.
Solution:
Question 11. Which of the following is not a forest product?
(i) Gum
(ii) Plywood
(iii) Sealing wax
(iv) Kerosene
Solution 11.
(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.
Solution 12.
Statement (ii) Plants and animals in a forest are not dependent on one another are not correct
Question 13. Micro-organisms act upon the dead plants to produce
(i) sand (ii) mushrooms (iii) humus (iv) wood
Solution 13.
(iii) humus