NCERT Science Class 10 Chapter 14 Our Environment CBSE Board Sample Problems Very Short Answer

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Question

List two natural ecosystems.

Solution

Forest, Lake

Question

Name the gas which ¡s produced due to incomplete combustion of fossil fuel?

Solution

Carbon monoxide

Question

Why is excessive use of CFCs a cause of concern?

Solution

When CFCs reach upper layers of the atmosphere, they cause depletion of ozone layer, and allow harmful UV radiations to reach the surface of the earth to create health hazards.

Question

What is 10 percent law?

Solution

  • Only 10% of energy is transferred to the next trophic level.

  • The remaining 90% energy is used in life processes (digestion, growth, reproduction etc.) by present trop hic level.

Question

What is an ecosystem?

Solution

All the interacting organisms in an area together with the nonliving constituents of the environment form an ecosystem. E.g., forest, pond etc.

Question

Some substances cannot be broken down in nature. What are they called?

Solution

Ans: Substances that are not broken-down by biological processes are called

Non-biodegradable.

Question

What has led to formation of ozone holes?

Solution

Ans: Decrease in ozone in stratosphere is linked to release of

Synthetic chemicals like Chlorofluorocarbons

Question

What is a food web?

Solution

The inter locking pattern of various food chains is referred as food web

Question

Why flow of energy in a food chain is considered unidirectional?

Solution

Energy captured by autotrophs does not revert back to the solar input and it passes to the herbivores

Question

In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:

a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).

c) Assertion (A) is true but reason(R) is false.

d) Assertion (A) is false but reason(R) is true.

Assertion: A network of food chains existing together in an ecosystem is known as food web.

Reason: An animal like kite cannot be a part of a food web.

Solution

(c) Assertion (A) is true but reason (R) is false.

Question

In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:

a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).

b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).

c) Assertion (A) is true but reason (R) is false.

d) Assertion (A) is false but reason(R) is true.

Assertion: Green plants of the ecosystem are the transducers.

Reason: Producers trap the radiant energy of the sun and change it into chemical energy.

Solution

(a) Both assertion (A) and reason (R) are true and reason

Question

Choose the correct option.

Replacing of plastic cups by the paper cups for selling tea on train is preferred because

a) Paper cups are more aesthetic

b) Paper cups are more hygienic

c) Paper cups are cheaper

d) Paper cups are biodegradable and eco-friendly

Solution

(4) Paper cups are biodegradable and eco- friendly

Question

Choose the correct option.

Trophic levels are formed by-

a) Only plants

b) Only animals

c) Only carnivores

d) Organisms linked in food chain

Solution

(d) Organisms linked in food chain

Question

Fill in the blanks

Gardens and crop fields are examples of

Solution

Artificial Ecosystem

Question

Fill in the blank

The contamination of air by adding gases, smoke and ash is called.

Solution

Air pollution

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