NCERT Class 10 Science Chapter 13 Our Environment Question Answer Solution For School Students of Class 10th. We also Provides Notes and Important Questions for Class 10 Science. NCERT Class 10th Science book is applied in mostly boards like CBSE, HBSE, RBSE, Up Board, MP Board and also some other state boards.
NCERT Class 10 Science Chapter 13 Our Environment internal and textual Question Answer for CBSE, HBSE, RBSE, UK Board, HP Board, MP Board and Other Boards Solution.
Our Environment Class 10 Science Chapter 13 Question Answer (Internal + Textual)
Internal Question Answer of Chapter 13
Internal Question Page 212
Q1. What are trophic levels ? Give an example of a food chain and state the different trophic levels in it.
Ans. Trophic levels are the step or level of the food chain at which transfer of food (or energy) takes place from one organism to another organism.
Example. Green plants → Deer → Tiger
In this food chain, green plants are at first trophic level, Deer is at second trophic level and tiger is at the third trophic level.
Q2. What is the role of decomposers in the ecosystem ?
Ans. Decomposers are the microorganisms comprising bacteria and fungi which break down the complex organic substances into simple inorganic substances.
Internal Question Page 214
Q1. Why are some substances biodegradable and some non-biodegradable ?
Ans. Those substances which can be decomposed by micro-organisms are called biodegradable substances. eg – fruits, paper, cotton, vegetables etc.
On the other hand, those substances which cann’t be decomposed by micro-organisms are called non-biodegradable substances. eg – plastic, polythene, DDT etc.
Q2. Give any two ways in which biodegradable substances would affect the environment.
Ans. (i) Decomposition of biodegradable substances which cause air pollution.
(ii) This will also cause water pollution.
Q3. Give any two ways in which non-biodegradable substances would affect the environment.
Ans. (i) Non-biodegradable pesticides like DDT enter the food chain and cause biomagnification in humans and other animals.
(ii) They contaminate soil and water as they cannot be decomposed by micro-organisms.
Internal Question Page 216
Q1. What is ozone and how does it affect any ecosystem ?
Ans. Ozone (O3) is a molecule formed by three atoms of oxygen. At the higher levels of atmosphere, it protects the surface of the earth from ultraviolet (UV) radiation from the Sun. This radiation is highly damaging as it can cause skin cancer in human beings.
Q2. How can you help in reducing the problem of waste disposal ? Give any two methods.
Ans. (i) By recycling the non-biodegradable waste material.
(ii) By minimizing the use of disposable articles and promoting the use of recycled articles.
Textual Question Answer of Chapter 13
Q1. Which of the following groups contain only biodegradable items?
(a) Grass, flowers and leather
(b) Grass, wood and plastic
(c) Fruit-peels, cake and lime-juice
(d) Cake, wood and grass
Ans. (b) Grass, wood and plastic
Q2. Which of the following constitute a food-chain?
(a) Grass, wheat and mango
(b) Grass, goat and human
(c) Goat, cow and elephant
(d) Grass, fish and goat
Ans. (b) Grass, goat and human
Q3. Which of the following are environment-friendly practices?
(a) Carrying cloth-bags to put purchases in while shopping
(b) Switching off unnecessary lights and fans
(c) Walking to school instead of getting your mother to drop you on her scooter
(d) All of the above
Ans. (d) All of the above
Q4. What will happen if we kill all the organisms in one trophic level?
Ans. If we kill all the organisms in one trophic level, the food supply in next trophic level will be affected which will cause imbalance of ecosystem.
Q5. Will the impact of removing all the organisms in a trophic level be different for different trophic levels? Can the organisms of any trophic level be removed without causing any damage to the ecosystem?
Ans. Yes, the removal of all the organisms in a trophic level will be different for different trophic levels.
For example : If we remove all producers, the upper trophic levels will be disturbed as upper trophic levels are dependent on lower levels. But if we remove consumers, then there will be increase in producers.
Q6. What is biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?
Ans. Biological magnification : It is defined as the the process of accumulation of non-degradable chemicals in living organisms at a concentration higher than that occurring in the inorganic, non-living environment.
The levels of magnification increases at each trophic level . As human beings occupy the top level in any food chain, the biological magnification is maximum for human beings.
Q7. What are the problems caused by the non-biodegradable wastes that we generate?
Ans. Non-biodegradable substances may be inert and simply persist in the environment for long time or may harm the various members of the eco-system.
Example – Non-biodegradable pesticides like DDT enter the food chain and cause biomagnification in humans and other animals.
Q8. If all the waste we generate is biodegradable, will this have no impact on the environment?
Ans. If all the wastes we generate is biodegradable, it will have only short term impact on environment, the action of decomposers will be slow down and some air and water pollution will be caused. However, in longer term, there will be no impact of biodegradable wastes on the environment.
Q9. Why is damage to the ozone layer a cause for concern? What steps are being taken to limit this damage?
Ans. Because depletion of ozone layer allows UV radiation on the earth surface which cause skin cancer in human beings.
To limit this damage, in 1987, the United Nations Environment Programme (UNEP) succeeded in forging an agreement to freeze CFC production, which cause depletion of ozone.