MCQ Questions for Class 10 Science: Ch 15 Our Environment
1. Which one of the following will undergo fastest bio-degradation?
(a) Mango seed
(b) Wood
(c) Mango peel
(d) Mango pulp
► (d) Mango pulp
2. First link in any food chain is usually green plants because
(a) they are widely distributed
(b) they are fixed at one place in the soil
(c) they alone have the capacity to synthesise food using sunlight
(d) there are more herbivores than carnivores
► (c) they alone have the capacity to synthesise food using sunlight
3. In an ecosystem, herbivores represent
(a) producers
(b) primary consumers
(c) secondary consumers
(d) decomposers
► (b) primary consumers
4. Which of the following is non- biodegradable?
(a) Wool
(b) Nylon
(c) Animal bones
(d) Tea leaves
► (b) Nylon
5. Ozone layer is damaged by-
(a) methane
(b) carbon-dioxide
(c) Sulphur-dioxide
(d) CFCs
► (d) CFCs
6. A food chain always starts with
(a) respiration
(b) photosynthesis
(c) decay
(d) nitrogen fixation
► (b) photosynthesis
7. 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
► (b) man
8. 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
► (d) decrease in energy at higher trophic levels
9. 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
► (a) producer → consumer → decomposer
10. Excessive exposure to ultraviolet radiation causes
(a) inflammation of liver
(b) cancer of skin
(c) damage to the lungs
(d) jaundice
► (b) cancer of skin
11. Which of the following is an autotroph?
(a) Lion
(b) Insect
(c) Tree
(d) Mushroom
► (c) Tree
12. Trophic level in an ecosystem represents
(a) oxygen level
(b) water level
(c) energy level
(d) salt level
► (c) energy level
13. Which of the following is biodegradable?
(a) Plastic mugs
(b) Leather belts
(c) Silver foil
(d) Iron nails
► (b) Leather belts
14. Which of the following is non-biodegradable-
(a) paper
(b) wood
(c) cloth
(d) plastic
► (d) plastic
15. In the garden ecosystem, which of the following are producers?
(a) Insects
(b) Snakes
(c) Grasses
(d) Rabbits
► (c) Grasses
16. Which of the following is biodegradable?
(a) Aluminium can
(b) Polythene bag
(c) Cowdung
(d) DDT
► (c) Cowdung
17. Which of the following is not a terrestrial ecosystem-
(a) forest
(b) desert
(c) aquarium
(d) grassland
► (c) aquarium
18. Which one of the following pairs belong to the category of primary consumers?
(a) Eagle and snake
(b) Grasshoppers & cattle
(c) Snake and frog
(d) Water beetles & fish
► (b) Grasshoppers & cattle
19. 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.
► (d) The population of lions decreases and grass increases.
20. The depletion of the ozone layer causes
(a) global wanning
(b) earthquakes
(c) increased UV radiations
(d) acid rain
► (c) increased UV radiations
21. Which of the following is an abiotic component of an ecosystem?
(a) Humus
(b) Bacteria
(c) Plants
(d) Fungi
► (a) Humus
22. Acid rain is caused by the oxides of
(a) carbon
(b) nitrogen only
(c) sulphur only
(d) sulphur and nitrogen
► (d) sulphur and nitrogen
23. 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
► (a) convert organic material to inorganic forms
24. Which of the two in the following sets belong to the same trophic level?
(a) Grass : Grasshopper
(b) Goat : Spider
(c) Hawk : Rat
(d) Frog : Lizard
► (d) Frog : Lizard
25. The second trophic level is always of-
(a) herbivores
(b) autotrophs
(c) carnivores
(c) producers
► (a) herbivores
26. The ecosystem of earth is known as-
(a) biome
(b) community
(c) biosphere
(c) association
► (c) biosphere
27. 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%
► (a) 1%
28. Flow of energy in an ecosystem is always-
(a) unidirectional
(b) bidirectional
(c) multidirectional
(d) no specific direction.
► (a) unidirectional
29. In natural ecosystems, decomposers include-
(a) only bacteria and fungi
(b) only microscopic animals
(c) herbivores and carnivores
(d) both (b) and (c)
► (a) only bacteria and fungi
30. Assertion: Ozone layer is getting depleted at upper atmosphere which is a cause of concern.
Reason: CFC reacts with ozone and breaks it.
(a) they are widely distributed
(b) they are fixed at one place in the soil
(c) they alone have the capacity to synthesise food using sunlight
(d) there are more herbivores than carnivores
► (c) they alone have the capacity to synthesise food using sunlight
3. In an ecosystem, herbivores represent
(a) producers
(b) primary consumers
(c) secondary consumers
(d) decomposers
► (b) primary consumers
4. Which of the following is non- biodegradable?
(a) Wool
(b) Nylon
(c) Animal bones
(d) Tea leaves
► (b) Nylon
5. Ozone layer is damaged by-
(a) methane
(b) carbon-dioxide
(c) Sulphur-dioxide
(d) CFCs
► (d) CFCs
6. A food chain always starts with
(a) respiration
(b) photosynthesis
(c) decay
(d) nitrogen fixation
► (b) photosynthesis
7. 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
► (b) man
8. 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
► (d) decrease in energy at higher trophic levels
9. 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
► (a) producer → consumer → decomposer
10. Excessive exposure to ultraviolet radiation causes
(a) inflammation of liver
(b) cancer of skin
(c) damage to the lungs
(d) jaundice
► (b) cancer of skin
11. Which of the following is an autotroph?
(a) Lion
(b) Insect
(c) Tree
(d) Mushroom
► (c) Tree
12. Trophic level in an ecosystem represents
(a) oxygen level
(b) water level
(c) energy level
(d) salt level
► (c) energy level
13. Which of the following is biodegradable?
(a) Plastic mugs
(b) Leather belts
(c) Silver foil
(d) Iron nails
► (b) Leather belts
14. Which of the following is non-biodegradable-
(a) paper
(b) wood
(c) cloth
(d) plastic
► (d) plastic
15. In the garden ecosystem, which of the following are producers?
(a) Insects
(b) Snakes
(c) Grasses
(d) Rabbits
► (c) Grasses
16. Which of the following is biodegradable?
(a) Aluminium can
(b) Polythene bag
(c) Cowdung
(d) DDT
► (c) Cowdung
17. Which of the following is not a terrestrial ecosystem-
(a) forest
(b) desert
(c) aquarium
(d) grassland
► (c) aquarium
18. Which one of the following pairs belong to the category of primary consumers?
(a) Eagle and snake
(b) Grasshoppers & cattle
(c) Snake and frog
(d) Water beetles & fish
► (b) Grasshoppers & cattle
19. 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.
► (d) The population of lions decreases and grass increases.
20. The depletion of the ozone layer causes
(a) global wanning
(b) earthquakes
(c) increased UV radiations
(d) acid rain
► (c) increased UV radiations
21. Which of the following is an abiotic component of an ecosystem?
(a) Humus
(b) Bacteria
(c) Plants
(d) Fungi
► (a) Humus
22. Acid rain is caused by the oxides of
(a) carbon
(b) nitrogen only
(c) sulphur only
(d) sulphur and nitrogen
► (d) sulphur and nitrogen
23. 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
► (a) convert organic material to inorganic forms
24. Which of the two in the following sets belong to the same trophic level?
(a) Grass : Grasshopper
(b) Goat : Spider
(c) Hawk : Rat
(d) Frog : Lizard
► (d) Frog : Lizard
25. The second trophic level is always of-
(a) herbivores
(b) autotrophs
(c) carnivores
(c) producers
► (a) herbivores
26. The ecosystem of earth is known as-
(a) biome
(b) community
(c) biosphere
(c) association
► (c) biosphere
27. 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%
► (a) 1%
28. Flow of energy in an ecosystem is always-
(a) unidirectional
(b) bidirectional
(c) multidirectional
(d) no specific direction.
► (a) unidirectional
29. In natural ecosystems, decomposers include-
(a) only bacteria and fungi
(b) only microscopic animals
(c) herbivores and carnivores
(d) both (b) and (c)
► (a) only bacteria and fungi
30. Assertion: Ozone layer is getting depleted at upper atmosphere which is a cause of concern.
Reason: CFC reacts with ozone and breaks it.
(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.
► (a) Both A and R are true and R is the correct explanation of A.
31. 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.
31. 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.
► (a) Both A and R are true and R is the correct explanation of A.
32. Assertion: Biodegradable waste and non biodegradable waste should be discarded separately,
Reason: Biodegradable waste are not harmful.
► (a) Both A and R are true and R is the correct explanation of A.
32. Assertion: Biodegradable waste and non biodegradable waste should be discarded separately,
Reason: Biodegradable waste are not harmful.
(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.
► (c) A is true but R is false.
► (c) A is true but R is false.