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 ยกs 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