Worksheet: Our Environment | Science Class 10 PDF Download

Fill in the blanks

Q1: Producers always contain __________pigments.

Q2: A position in a food chain is called a __________ .

Q3: __________constitute the first trophic level.

Q4: A series of interconnected food chains representing the feeding relationship of the organisms within an ecosystem is called__________ .

Q5: Autotrophs capture the energy present in sunlight and convert it into__________ .

Q6: In a grassland ecosystem a hawk represents the __________.

Mark the statements true (T) or false(F)

Q1:The frog that eats the grasshopper is a secondary consumer.

Q2: Sewage may be used to produce biogas.

Q3: Decomposers are also called saprotrophs.
Q4: All green plants and blue-green algae are producers.

Assertion and Reason Type Questions

Q1: Following questions consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:
Assertion: Polythene bags and plastic containers are non-biodegradable substances.
Reason: They can be broken down by microorganisms in natural simple harmless substances.
(a) Both ‘A’ and ‘R’ are true and ‘R’ is correct explanation of the Assertion.
(b) Both ‘A’ and ‘R’ are true but ‘R’ is not correct explanation of the Assertion.
(c) ‘A’ is true but ‘R’ is false.
(d) ‘A’ is false but ‘R’ is true.

Q2: Following questions consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:
Assertion: Ozone is formed in upper atmosphere by O2 in presence of UV radiations.
Reason: Ozone depletion will lead to UV rays reaching earth which may cause skin cancer.
(a) Both ‘A’ and ‘R’ are true and ‘R’ is correct explanation of the Assertion.
(b) Both ‘A’ and ‘R’ are true but ‘R’ is not correct explanation of the Assertion.
(c) ‘A’ is true but ‘R’ is false.
(d) ‘A’ is false but ‘R’ is true.

Q3: Following questions consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:
Assertion: Tropical rain forests are disappearing fast from developing countries such as India
Reason: No value is attached to these forests because these are poor in biodiversity.
(a) Both ‘A’ and ‘R’ are true and ‘R’ is correct explanation of the Assertion.
(b) Both ‘A’ and ‘R’ are true but ‘R’ is not correct explanation of the Assertion.
(c) ‘A’ is true but ‘R’ is false.
(d) ‘A’ is false but ‘R’ is true.

Q4: Following questions consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:
Assertion: Aquarium needs regular cleaning
Reason: There are no microbes to clean water in aquarium, therefore, it needs to be regularly cleaned
(a) Both ‘A’ and ‘R’ are true and ‘R’ is correct explanation of the Assertion.
(b) Both ‘A’ and ‘R’ are true but ‘R’ is not correct explanation of the Assertion.
(c) ‘A’ is true but ‘R’ is false.
(d) ‘A’ is false but ‘R’ is true.

Q5: Following questions consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:
Assertion: Biotic components of ecosystem continuously require energy to carry on life processes.
Reason: Biotic components are the nonliving components of the ecosystem
(a) Both ‘A’ and ‘R’ are true and ‘R’ is correct explanation of the Assertion.
(b) Both ‘A’ and ‘R’ are true but ‘R’ is not correct explanation of the Assertion.
(c) ‘A’ is true but ‘R’ is false.
(d) ‘A’ is false but ‘R’ is true.

Q6: Following questions consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:
Assertion: Aquariums are known as the man made ecosystems
Reason: Aquariums are created and maintained by humans
(a) Both ‘A’ and ‘R’ are true and ‘R’ is correct explanation of the Assertion.
(b) Both ‘A’ and ‘R’ are true but ‘R’ is not correct explanation of the Assertion.
(c) ‘A’ is true but ‘R’ is false.
(d) ‘A’ is false but ‘R’ is true.

Q7: Following questions consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:
Assertion: First trophic level in a food chain is always a green plant
Reason: Green plants are called producers
(a) Both ‘A’ and ‘R’ are true and ‘R’ is correct explanation of the Assertion.
(b) Both ‘A’ and ‘R’ are true but ‘R’ is not correct explanation of the Assertion.
(c) ‘A’ is true but ‘R’ is false.
(d) ‘A’ is false but ‘R’ is true.

Q8: Following questions consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:
Assertion: The concentration of harmful chemicals is least in human beings.
Reason: Man is at the apex of the food chain.
(a) Both ‘A’ and ‘R’ are true and ‘R’ is correct explanation of the Assertion.
(b) Both ‘A’ and ‘R’ are true but ‘R’ is not correct explanation of the Assertion.
(c) ‘A’ is true but ‘R’ is false.
(d) ‘A’ is false but ‘R’ is true.

Q9: Following questions consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:
Assertion: Decomposers keep the environment clean.
Reason: They recycle matter by breaking down the organic remains and waste products of plants and animals.
(a) Both ‘A’ and ‘R’ are true and ‘R’ is correct explanation of the Assertion.
(b) Both ‘A’ and ‘R’ are true but ‘R’ is not correct explanation of the Assertion.
(c) ‘A’ is true but ‘R’ is false.
(d) ‘A’ is false but ‘R’ is true.

Q10: Following questions consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:
Assertion: Man is a herbivore.
Reason: Omnivores eat both plant food and meat of animals.
(a) Both ‘A’ and ‘R’ are true and ‘R’ is correct explanation of the Assertion.
(b) Both ‘A’ and ‘R’ are true but ‘R’ is not correct explanation of the Assertion.
(c) ‘A’ is true but ‘R’ is false.
(d) ‘A’ is false but ‘R’ is true.

Short Answer Type Questions

Q1: Give any two ways in which biodegradable substances would affect the environment.

Q2: Differentiate between natural and artificial ecosystem.

Q3: List any two advantages of decomposers to the environment?

Q4: Write the harmful effects of using plastic bags, on the environment. Suggest alternatives to plastic bags. 

Q5: (a) Define ecosystem.
(b) Autotrophs are at the first level of food chain. Give reason.
(c) In a food chain of frogs, grass, insects and snakes, assign trophic level to frogs. To which category of consumers do they belongs to?

Q6: (i) Create a terrestrial food chain depicting four trophic levels.
(ii) Why do we not find food chains of more than four trophic levels in nature?

Q7: Write the essential function performed by ozone at the higher levels of the Earth’s atmosphere?
How is it produced? Name the synthetic chemicals mainly responsible for the drop of amount of ozone in the atmosphere. How can the use of these chemicals be reduced?

Q8: Give reason to justify the following:
The existence of decomposers is essential in a biosphere. 

Q9: How is ozone both beneficial and damaging? How can we prevent the damaging effect of ozone?

Q10: (a) Explain the role of UV radiation in producing ozone layer.
(b) Mention the reaction involved.
(c) Why is excessive use of CFCs a cause of concern?

Q11: How will you create an artificial aquatic ecosystem, which is self-sustainable?

Long Answer Type Questions

Q1: Suggest suitable mechanisms for waste management in fertiliser industries.

Q2: Why is damage to the ozone layer a cause for concern? What steps are being taken to limit this damage? 

Q3: Explain some harmful effects of agricultural practices on the environment.

Q4: Suggest any four activities in daily life which are eco-friendly.

Q5: Name the wastes which are generated in your house daily. What measures would you take for their disposal?

Q6: (a) Indicate the flow of energy in an ecosystem. Why is it unidirectional? Justify.
(b) What will happen if decomposers are absent in an ecosystem?

You can access the solutions to this worksheet here.