Question 1.
Assertion: Vegetarian food habit is more beneficial to organisms.
Reason: Only 10% energy is available as food from one trophic level to next.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
(e) Both A and R are false.

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

Question 2.
In natural ecosystems, decomposers include-
(a) only bacteria and fungi
(b) only microscopic animals
(c) herbivores and carnivores
(d) both (b) and (c)

Answer
(a) only bacteria and fungi

Question 3.
The percentage of solar radiation absorbed by all the green plants for the process of photosynthesis is about-
(a) 1%
(b) 8%
(c) 5%
(d) 10%

Answer
(a) 1%

Question 4.
The second trophic level is always of-
(a) herbivores
(b) autotrophs
(c) carnivores
(c) producers

Answer
(a) herbivores

Question 5.
The decomposers in an ecosystem-
(a) convert organic material to inorganic forms
(b) convert inorganic material to simpler forms
(c) convert inorganic material into organic compound
(d) do not break down organic compound

Answer
(a) convert organic material to inorganic forms

Question 6.
Which of the following is an abiotic component of an ecosystem?
(a) Humus
(b) Bacteria
(c) Plants
(d) Fungi

Answer
(a) Humus

Question 7.
What will happen if all the deer are killed in the given food chain?
Grass → Deer → Lion
(a) The population of grass decreases.
(b) The population of lions increases.
(c) The population of lions remains unchanged.
(d) The population of lions decreases and grass increases.

Answer
(d) The population of lions decreases and grass increases.

Question 8.
Which of the following is not a terrestrial ecosystem–
(a) forest
(b) desert
(c) aquarium
(d) grassland

Answer
(c) aquarium

Question 9.
In the garden ecosystem, which of the following are producers?
(a) Insects
(b) Snakes
(c) Grasses
(d) Rabbits

Answer
(c) Grasses

Question 10.
Which of the following is biodegradable?
(a) Plastic mugs
(b) Leather belts
(c) Silver foil
(d) Iron nails

Answer
(b) Leather belts

Question 11.
Which of the following is an autotroph?
(a) Lion
(b) Insect
(c) Tree
(d) Mushroom

Answer
(c) Tree

Question 12.
Which of the following is a logical sequence of food chain
(a) producer → consumer → decomposer
(b) producer → decomposer → consumer
(c) consumer → producer → decomposer
(d) decomposer → producer → consumer

Answer
(a) producer → consumer → decomposer

Question 13.
A food chain comprising birds, green plants, fish and man. The concentration of harmful chemical entering the food chain will be maximum in
(a) green plants
(b) man
(c) birds
(d) fish

Answer
(b) man

Question 14.
Ozone layer is damaged by-
(a) methane
(b) carbon-dioxide
(c) Sulphur-dioxide
(d) CFCs

Answer
(d) CFCs

Question 15.
In an ecosystem, herbivores represent
(a) producers
(b) primary consumers
(c) secondary consumers
(d) decomposers

Answer
(b) primary consumers

Important Link

Quick Revision Notes : Our Environment

NCERT Solution :Our Environment

IMPORTANT QUESTION :Our Environment

Click here for Free Video Lectures