Class 10 Science - Chapter Our Environment NCERT Solutions | Give any two ways in which biodegradable

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

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

How can you help in reducing the problem of waste disposal? Give any two methods.

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 would be the electron dot structure of a molecule of sulphur which is made up of eight atoms of sulphur? (Hint – The eight atoms of sulphur are joined together in the form of a ring.)

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

Draw a schematic diagram of a circuit consisting of a battery of three cells of 2 V each, a 5 Ω resistor, an 8 Ω resistor, and a 12 Ω resistor, and a plug key, all connected in series.

What are the components of the transport system in human beings? What are the functions of these components?

What are plant hormones?

We saw in this chapter that there are four main stakeholders when it comes to forests and wildlife. Which among these should have the authority to decide the management of forest produce? Why do you think so?

What are the limitations of the energy that can be obtained from the oceans?

Let the resistance of an electrical component remains constant while the potential difference across the two ends of the component decreases to half of its former value. What change will occur in the current through it?

A piece of wire of resistance R is cut into five equal parts. These parts are then connected in parallel. If the equivalent resistance of this combination is R′, then the ratio R/R′ is –

(a) 1/25        (b) 1/5        (c) 5        (d) 25

How has the traditional use of wind and water energy been modified for our convenience?