NCERT Class 8 Science MCQ | Chapter 12: How Nature Works in Harmony
1. What is a habitat?
(A) A place where only plants live
(B) A place that provides suitable conditions for an organism to live and grow
(C) A place where only animals live
(D) A place without non-living components
Answer: (B) A place that provides suitable conditions for an organism to live and grow
2. Which of the following is a biotic component of a habitat?
(A) Water
(B) Soil
(C) Temperature
(D) Fish
Answer: (D) Fish
3. Which of the following is an abiotic component of a habitat?
(A) Grass
(B) Birds
(C) Water
(D) Fish
Answer: (C) Water
4. What is a population?
(A) Different species living in different habitats
(B) A group of organisms of the same type living in a habitat at a given time
(C) All the non-living things in a habitat
(D) All ecosystems on Earth
Answer: (B) A group of organisms of the same type living in a habitat at a given time
5. A community consists of:
(A) Only one population
(B) Different populations sharing the same habitat
(C) Only non-living components
(D) Only plants of one species
Answer: (B) Different populations sharing the same habitat
6. Which statement correctly describes an ecosystem?
(A) It contains only living organisms
(B) It contains only non-living components
(C) It is formed by interactions between biotic and abiotic components
(D) It contains only plants and animals
Answer: (C) It is formed by interactions between biotic and abiotic components
7. Which of the following is an aquatic ecosystem?
(A) Forest
(B) Grassland
(C) Pond
(D) Farm
Answer: (C) Pond
8. Which of the following is a terrestrial ecosystem?
(A) Lake
(B) River
(C) Pond
(D) Forest
Answer: (D) Forest
9. Organisms that make their own food are called:
(A) Consumers
(B) Decomposers
(C) Producers
(D) Parasites
Answer: (C) Producers
10. Which process allows green plants to make their own food?
(A) Respiration
(B) Photosynthesis
(C) Decomposition
(D) Pollination
Answer: (B) Photosynthesis
11. Which of the following is a herbivore?
(A) Deer
(B) Leopard
(C) Eagle
(D) Tiger
Answer: (A) Deer
12. An organism that eats both plants and animals is called a:
(A) Herbivore
(B) Carnivore
(C) Omnivore
(D) Producer
Answer: (C) Omnivore
13. Which of the following is an example of a carnivore?
(A) Deer
(B) Hare
(C) Leopard
(D) Grass
Answer: (C) Leopard
14. What does a food chain show?
(A) The physical conditions of a habitat
(B) A sequence showing who eats whom in an ecosystem
(C) The number of organisms in a habitat
(D) The movement of water in an ecosystem
Answer: (B) A sequence showing who eats whom in an ecosystem
15. In the food chain Grass → Grasshopper → Frog → Snake → Eagle, which organism is the producer?
(A) Grass
(B) Grasshopper
(C) Frog
(D) Eagle
Answer: (A) Grass
16. Which organisms occupy the first trophic level in a food chain?
(A) Herbivores
(B) Carnivores
(C) Producers
(D) Decomposers
Answer: (C) Producers
17. What is a food web?
(A) A single food chain
(B) A network formed by interconnected food chains
(C) A group of abiotic components
(D) A habitat containing only plants
Answer: (B) A network formed by interconnected food chains
18. Which organisms break down dead plants and animals into simpler substances?
(A) Producers
(B) Herbivores
(C) Decomposers
(D) Carnivores
Answer: (C) Decomposers
19. Which of the following is an example of a decomposer?
(A) Deer
(B) Mushroom
(C) Eagle
(D) Grasshopper
Answer: (B) Mushroom
20. What is decomposition important for?
(A) Increasing pollution
(B) Recycling nutrients back into the environment
(C) Stopping plant growth
(D) Removing oxygen from the atmosphere
Answer: (B) Recycling nutrients back into the environment
21. What type of interaction occurs when both organisms benefit?
(A) Parasitism
(B) Commensalism
(C) Mutualism
(D) Competition
Answer: (C) Mutualism
22. Which is an example of mutualism given in the chapter?
(A) Ticks and dogs
(B) Orchids and trees
(C) Honeybees and flowers
(D) Leopard and deer
Answer: (C) Honeybees and flowers
23. In commensalism:
(A) Both organisms are harmed
(B) Both organisms benefit
(C) One organism benefits while the other is unaffected
(D) One organism benefits while the other is harmed
Answer: (C) One organism benefits while the other is unaffected
24. What happens when an organism benefits while another organism is harmed?
(A) Mutualism
(B) Commensalism
(C) Parasitism
(D) Cooperation
Answer: (C) Parasitism
25. Which of the following can threaten the balance of ecosystems?
(A) Deforestation
(B) Pollution
(C) Overuse of natural resources
(D) All of the above
Answer: (D) All of the above
NCERT Class 8 Science MCQ | Chapter 12: How Nature Works in Harmony
Assertion–Reason Questions
Directions: Choose the correct option:
(A) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
(B) Both Assertion and Reason are true, but Reason is not the correct explanation of Assertion.
(C) Assertion is true, but Reason is false.
(D) Assertion is false, but Reason is true.
1. Assertion: An ecosystem is formed through interactions between biotic and abiotic components.
Reason: Organisms depend on components such as air, water, soil, sunlight, and temperature for their survival.
Answer: (A)
2. Assertion: Decomposers are important for maintaining nutrient cycles in an ecosystem.
Reason: Decomposers break down dead plants and animals into simpler substances and return nutrients to the soil.
Answer: (A)
3. Assertion: A food web is more complex than a food chain.
Reason: A food web consists of several interconnected food chains.
Answer: (A)
4. Assertion: In mutualism, both organisms benefit from their interaction.
Reason: Honeybees obtain nectar from flowers while helping in pollination.
Answer: (A)
5. Assertion: Human activities can disturb the balance of an ecosystem.
Reason: Activities such as deforestation, pollution, habitat loss, and overuse of natural resources can affect organisms and their surroundings.
Answer: (A)
