Class 10 Science - Chapter Our Environment NCERT Solutions | How can you help in reducing the problem

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

Give any two ways in which biodegradable substances would affect the environment.

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

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

Why are some substances biodegradable and some non-biodegradable?

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

What is ozone and how does it affect any ecosystem?

What are trophic levels? Give an example of a food chain and state the different trophic levels in it.

What is the role of decomposers in the ecosystem?

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

Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.

What is a good source of energy?

Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?

What changes can you make in your habits to become more environment-friendly?

What is the difference between a reflex action and walking?

What is the importance of DNA copying in reproduction?

If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?

Why should a magnesium ribbon be cleared before burning in air?

Define the principal focus of a concave mirror.

You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?

What is the function of receptors in our body? Think of situations where receptors do not work properly. What problems are likely to arise?

An electric oven of 2 kW power rating is operated in a domestic electric circuit (220 V) that has a current rating of 5 A. What result do you expect? Explain.

Compare and contrast bio-mass and hydro electricity as sources of energy.

What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration.

Equal lengths of magnesium ribbons are taken in test tubes A and B. Hydrochloric acid (HCl) is added to test tube A, while acetic acid (CH₃COOH) is added to test tube B. Amount and concentration taken for both the acids are same. In which test tube will the fizzing occur more vigorously and why?

An electric motor takes 5 A from a 220 V line. Determine the power of the motor and the energy consumed in 2 h.

Differentiate between metal and non-metal on the basis of their chemical properties.

How are involuntary actions and reflex actions different from each other?

One-half of a convex lens is covered with a black paper. Will this lens produce a complete image of the object? Verify your answer experimentally. Explain your observations.

What could be the reasons for adopting contraceptive methods?