NCERT Solutions helps the students of all classes to attain the right approach for precisely answering the textbook questions. These solutions develop a strong conceptual base in students which plays a major role in the later stages for successful competition of competitive exams.
CBSE NCERT Solutions for Class 7 Science Chapter 17:
What would happen if it rains heavily in your town? How does forest affect
The forest acts as a natural absorber of rainwater and allows it to seep. It helps
maintain the water table throughout the year. Forests not only help in controlling floods but also help maintain the flow of water in the streams so that we get a steady supply of water. On the other hand, if trees are not present, rain hits the ground directly and may flood the area around it. Heavy rain may also damages the soil. Roots of trees normally bind the soil together, but in their absence the soil is washed away or eroded.
There are so many forests in India. What difference will it make if we cut some
trees for a factory?
You have read about autotrophs, heterotrophs and saprotrophs. You have learnt
how green plants produce food. All animals, whether herbivores or carnivores, depend
ultimately on plants for food. Organisms which feed on plants often get eaten by other organisms, and so on. For example, grass is eaten by insects, which in turn, is taken by the frog. The frog is consumed by snakes. This is said to form a food chain: Grass→ insects→ frog→ snake→ eagle. Many food chains can be found in the forest. All food chains are linked. If anyone food chain is disturbed, it
affects other food chains. Every part of the forest is dependent on the other parts. If we remove one component, say trees, all other components would be affected.
How does forest maintain balance of oxygen and carbon dioxide in atmosphere?
The plants take carbon dioxide in and release oxygen through the process of
photosynthesis. The plants help to provide oxygen for animal respiration. Animal on the other hand breathe oxygen and releases carbon dioxide in the atmosphere. In this way, they maintain the balance of oxygen and carbon dioxide in the atmosphere.