10th Students Our Environment

Answers to Science Questions

**1. 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

Answer: (c) Fruit-peels, cake and lime-juice

**2. 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

Answer: (b) Grass, goat and human

**3. 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

Answer: (d) All of the above

**4. What will happen if we kill all the organisms in one trophic level?**

Answer: Killing all organisms in one trophic level will disrupt the food chain, causing a decrease in the population of the level above (due to lack of food) and an increase in the level below (due to reduced predation), potentially leading to ecosystem imbalance.

**5. 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?**

Answer: Yes, the impact varies; removing producers affects all levels, while removing top predators may cause overpopulation of prey. No, removing organisms from any trophic level will cause some damage due to interdependence in the ecosystem.

**6. What is biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?**

Answer: Biological magnification is the increasing concentration of toxic substances in organisms at higher trophic levels. Yes, levels are higher at higher trophic levels as toxins accumulate through the food chain.

**7. What are the problems caused by the non-biodegradable wastes that we generate?**

Answer: Non-biodegradable wastes cause soil and water pollution, harm wildlife, clog drains, and accumulate in landfills, posing long-term environmental and health hazards.

**8. If all the waste we generate is biodegradable, will this have no impact on the environment?**

Answer: No, even biodegradable waste can impact the environment by causing over-decomposition, releasing methane, and depleting oxygen in water bodies if not managed properly.

**9. Why is damage to the ozone layer a cause for concern? What steps are being taken to limit this damage?**

Answer: Damage to the ozone layer allows harmful UV radiation to reach Earth, increasing skin cancer and ecosystem damage. Steps include the Montreal Protocol, which phases out ozone-depleting substances like CFCs.