CBSE Class 10 Science Chapter-15 Our Environment – Free PDF Download
Free PDF download of Important Questions with Answers for CBSE Class 10 Science Chapter 15 – Our Environment prepared by expert Science teachers from latest edition of CBSE(NCERT) books only by CoolGyan to score more marks in CBSE board examination.
CBSE Class 10 Science Chapter-15 Our Environment Important Questions
CBSE Class 10 science Important Questions Chapter 15 – Our Environment
1 Mark Questions
1. A food chain always starts with
(a) respiration
(b) photosynthesis
(c) decay
(d) nitrogen fixation
Ans. Photosynthesis.
2. Ozone layer is damaged by-
(a) methane
(b) carbon-dioxide
(c) Sulphur-dioxide
(d) CFCs
Ans. CFCs.
3. Which of the following limits the number of trophic levels in a food chain?
(a) water
(b) polluted air
(c) deficient food supply
(d) decrease in energy at higher trophic levels
Ans. Decrease in energy at higher energy levels.
4. Name the main source of energy in self sustaining ecosystem?
Ans. Sun.
5.Write an aquatic food chain.
Ans. Phytoplankton 
Zooplankton Small fish large fish
6.Which of the following is non-biodegradable-
(a) paper
(b) wood
(c) cloth
(d) plastic
Ans. Plastic
7. Which of the following is not a terrestrial ecosystem-
(a) forest
(b) desert
(c) aquarium
(d) grassland
Ans. Aquarium
8. What will happen if deer is missing in the given food chain?
Grass Deer Tiger
(a) the population of tiger decreases and the population of grass increases
(b) the population of grass decreases
(c) tiger will start eating grass
(d) the population of tiger increases
Ans. Population of tiger increases and population of grass increases.
9. What is trophic level?
Ans. Various levels or steps in a food chain in which transfer of food takes place from one organism to another are called trophic levels.
10. Write a fresh water food chain?
Ans. Phytoplankton zooplankton small fish large fish
11.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
Ans. Convert organic material to inorganic forms.
12. The second trophic level is always of-
(a) herbivores
(b) autotrophs
(c) carnivores
(d) producers
Ans. Herbivores
13.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%
Ans. (a) 1%
14. Which of the following belong to the same trophic level: grasshopper, spider, grass, hawk, and lizard?
Ans. Grasshoppers and spider
15. What is acid rain?
Ans. Oxides of sulphur and nitrogen when dissolves in rain water form sulphuric acid and nitrous acid or nitric acid. The polluted rain with these acid is called acid rain.
16. The ecosystem of earth is known as-
(A) biome
(B) community
(C) biosphere
(D) association
Ans. Biosphere
17. Which of the following constitute a food chain?
(A) Grass, goat and human
(B) Goat, cow and elephant
(C) Grass fish and goat
(D) Grass, wheat and mango
Ans. Grass, goat, human.
18. Flow of energy in an ecosystem is always-
(A) Unidirectional
(B) bidirectional
(C) multidirectional
(D) no specific direction.
Ans. Unidirectional
19. Name the main source of energy in any self sustaining system.
Ans. Sun
20. Which of the following in not a part of biotic component of an ecosystem: water, algae, fish, bacteria?
Ans. Water
21. Which of the following limits the of trophic levels in a food chain-
(a) water
(b) polluted
(c) deficient food supply
(d) decrease in energy at higher trophic levels
Ans. Decrease in energy at higher trophic levels.
22. In natural ecosystems, decomposers include-
(a) only bacteria and fungi
(b) only microscopic animals
(c) herbivores and carnivores
(d) both (b) and (c)
Ans. Only bacteria and fungi
23. All living organisms of the earth constitute a-
(a) biosphere
(b) biotic community
(c) biome
(d) ecosystem
Ans. Biosphere
24. What are the various steps of food chains called?
Ans. Trophic levels
25.Which one is not biodegradable: paper, plastic, sewage?
Ans. Plastic
26.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
Ans. Groups (a), (c) and (d).
27.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.
Ans. (b) Grass, goat, human
28.Which of the following are environment-friendly practices?
(a) Carrying cloth-bag to put purchases in while shopping.
(b) Switching off unnecessary lights and fans.
(c) Walking to school instead of getting your mother to drop you on her scooter.
(d) All of the above.
Ans. (d) All of the above.
29. Construct a food chain composing the following Snake, Hawk, Rats, Plants.
Ans. Plants— Rats — Snake — Hawks
30. Name the process that is a direct outcome of excessive burning of fossil fuels?
Ans. Global warming is a direct outcome of excessive burning of fossil fuels.
31. Using Kuihads as disposable cups to serve tea in trains, proved to be a bad idea. Why?
Ans. Making Kulhads on large scales leads to the loss of top soil
32. Why is plastic not degraded by bacteria?
Ans. Plastic is not degraded by bacteria because they do not have enzymes to degrade plastic