Students can practice the best Class 8 Science MCQ and How Nature Works in Harmony Class 8 Science Curiosity Chapter 12 MCQ Online Test with Answers for exam preparation.
Class 8 Science Chapter 12 How Nature Works in Harmony MCQ
How Nature Works in Harmony MCQ
Class 8 Science Chapter 12 MCQ Online Test
Question 1.
Which of the following is an abiotic component of a habitat?
(a) Tree
(b) Lion
(c) Sunlight
(d) Earthworm
Answer:
(c) Sunlight
Question 2.
A frog lives both in water and on land. Which type of habitat is best suited for it?
(a) Desert
(b) Forest
(c) Grassland
(d) Pond
Answer:
(d) Pond
Question 3.
A forest loses most of its trees due to fire. Which component of the habitat is most directly affected?
(a) Wind
(b) Rocks
(c) Herbivores
(d) Rainfall
Answer:
(c) Herbivores
Question 4.
What does a population include in an ecosystem?
(a) All species in a forest
(b) One species in a specific area
(c) All living and non-living things
(d) All humans around the world
Answer:
(c) All living and non-living things
Question 5.
A community in an ecosystem is made up of
(a) only plants
(b) only animals
(c) several populations living together
(d) only abiotic components
Answer:
(c) several populations living together
Question 6.
Why is it important to maintain balance among populations in a community?
(a) To allow predators to overpopulate
(b) To protect only plants
(c) To maintain food chain and ecosystem health
(d) To increase competition
Answer:
(c) To maintain food chain and ecosystem health
Question 7.
In parasitism, the parasite
(a) benefits and harms the host
(b) benefits and helps the host
(c) does not affect the host
(d) dies after benefiting the host
Answer:
(a) benefits and harms the host
Question 8.
Which of the following best shows commensalism? (Competency Based Que.)
(a) Bacteria in human intestine producing vitamins
(b) Barnacles living on a whale without affecting it
(c) Cuckoo laying eggs in crow’s nest
(d) Tapeworm living in human intestine
Answer:
(b) Barnacles living on a whale without affecting it
Question 9.
A bird builds its nest on a tree, but the tree is neither harmed nor benefited. This is an example of
(a) Mutualism
(b) Parasitism
(c) Commensalism
(d) Competition
Answer:
(c) Commensalism
Question 10.
A fox that eats a rabbit is at which trophic level?
(a) First
(b) Second
(c) Third
(d) Fouth
Answer:
(c) Third
Question 11.
Which of the following is not a trophic level?
(a) Quaternary consumer
(b) Producers
(c) Primary consumers
(d) Abiotic components
Answer:
(d) Abiotic components
Question 12.
Which of these human activities is a major threat to ecosystems?
(a) Three plantation
(b) Afforestation
(c) Deforestation
(d) Rainwater harvesting
Answer:
(c) Deforestation
Question 13.
Which is not an abiotic factor in a forest ecosystem?
(a) Sunlight
(b) Soil pH
(c) Deer population
(d) Rainfall
Answer:
(c) Deer population
Question 14.
How do plants (biotic) interact with sunlight (abiotic)?
(a) By producing oxygen through respiration
(b) By using it for photosynthesis
(c) By reflecting it to stay cool
(d) By avoiding it to prevent drying
Answer:
(b) By using it for photosynthesis
Question 15.
A community in an ecosystem includes
(a) only plants and animals
(b) all living organisms interacting in an area
(c) only abiotic factors
(d) a single species and its environment
Answer:
(b) all living organisms interacting in an area
Question 16.
Which is a key function of ecosystems?
(a) Producing synthetic chemicals
(b) Recycling nutrients through decomposition
(c) Increasing pollution levels
(d) Reducing biodiversity
Answer:
(b) Recycling nutrients through decomposition
Question 17.
Which human activity most threatens ecosystems?
(a) Planting trees
(b) Recycling waste
(c) Using solar energy
(d) Overfishing
Answer:
(d) Overfishing
How Nature Works in Harmony Class 8 Assertion Reason Questions
The following questions consist of two statements. Assertion (A) and Reason (R). Answer the following questions by selecting the appropriate option given below.
(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
Question 1.
Assertion (A) A pond is a habitat.
Reason (R) It provides food, water, shelter, and space for aquatic plants and animals.
Answer:
(a) Both A and R are true and R is the correct explanation of A
Question 2.
Assertion (A) A forest community includes tigers, deer, trees, and microbes.
Reason (R) An individual consists of all living organisms in a particular habitat interacting with each other.
Answer:
(c) A is true, but R is false
Question 3.
Assertion (A) A change in the population of one species can affect the entire community..
Reason (R) Populations are interdependent in a community for food, shelter, and survival.
Answer:
(a) Both A and R are true and R is the correct explanation of A
Question 4.
Assertion (A) Decomposers are not essential for nutrient cycling in ecosystems.
Reason (R) They convert dead matter into usable nutrients for producers.
Answer:
(d) A is false, but R is true
Question 5.
Assertion (A) A pond is a self-sustaining ecosystem.
Reason (R) It has both biotic and abiotic components interacting.
Answer:
(a) Both A and R are true and R is the correct explanation of A.
Question 6.
Assertion (A) All bacteria in an ecosystem are harmful.
Reason (R) Decomposer bacteria recycle nutrients.
Answer:
(d) A is false, but R is true.
How Nature Works in Harmony Class 8 Case Based MCQ Questions
Question 1.
In a wetland area, algae and aquatic plants are the main producers. Small fish feed on algae, while bigger fish eat the smaller ones. Frogs feed on insects and are preyed upon by snakes and herons. Birds like herons eat fish and frogs. Decomposers like fungi and bacteria break down dead plants and animals, returning nutrients to the water and soil. (Competency Based Que.)
(i) Which of the following organisms are at the top of this wetland food web?
(a) Algae and aquatic plants
(b) Frogs and insects
(c) Herons and snakes
(d) Fungi and bacteria
Answer:
(c) Herons and snakes
(ii) If herons are removed from the food web, which of the following may happen?
(a) Algae population may crash
(b) Snake population may increase
(c) Frog population may increase
(d) Aquatic plant growth may slow
Answer
(c) Frog population may increase
How Nature Works in Harmony Class 8 Fill in the blanks
1. The living components of a habitat are called ……………………. factors.
Answer:
Biotic
2. Temperature, water, light, and soil are examples of ……………………. components.
Answer:
Abiotic
3. Animals depend on ……………………. for oxygen and water.
Answer:
Abiotic factors
4. The interaction between biotic components and abiotic components in an area forms an …………………….
Answer:
Ecosystem
5. A rise or fall in the population of one species affects the ……………………. as a whole.
Answer:
Community
6. A population can only survive if its basic ……………………. are fulfilled.
Answer:
Needs
7. ……………………… depicts who eat whom in an ecosystem.
Answer:
Food chain
8. Pollution, deforestation, and overfishing are major ……………………. to ecosystems.
Answer:
Threats
9. Animals that feed on both plants and other animals are called ………………………. .
Answer:
Omnivores
10. Organisms that break down dead organic matter into simpler substances are called ………………… .
Answer:
decomposers
11. Animals that feed on both plants and other animals are called ………………………. .
Answer:
Omnivores
12. Organisms that break down dead organic matter into simpler substances are called ………………… .
Answer:
decomposers
How Nature Works in Harmony Class 8 True or False
1. A habitat includes only the living organisms present in an area.
Answer:
False
2. Each species in a habitat has a different role.
Answer:
False
3. Temperature and rainfall affect the types of organisms found in a region.
Answer:
True
4. The balance between biotic and abiotic factors is necessary for ecosystem health.
Answer:
True
5. The number of individuals in a population can change overtime.
Answer:
True
6. Populations can only exist on land, not in water.
Answer:
False
7. Consumers break down dead organisms in an ecosystem.
Answer:
False
8. Fungi and bacteria are common decomposers.
Answer:
True
9. A food chain always starts with carnivores.
Answer:
False
10. Human-made ecosystems like agricultural fields are more stable than natural ecosystems because they are controlled by humans.
Answer:
False
11. In a predator-prey relationship, if the prey population decreases, the predator population will always decrease immediately.
Answer:
False
How Nature Works in Harmony Class 8 Match the following
Question 1.
Match the population to its likely community.
| Column I | Column II |
| A. Ants | 1. Polar region |
| B. Penguins | 2. Desert |
| C. Camels | 3. Grassland |
| D. Deer | 4. Forest |
Answer:
A – 4, B – 1, C – 2, D – 3
| Column I | Column II |
| A. Ants | 4. Forest |
| B. Penguins | 1. Polar region |
| C. Camels | 2. Desert |
| D. Deer | 3. Grassland |
Question 2.
Match the interaction with the example.
| Column I | Column II |
| A. Mutualism | 1. Two tigers fighting for territory |
| B. Parasitism | 2. Tick feeding on a cow |
| C. Commensalism | 3. Bird eating pests from buffalo’s back |
| D. Competition | 4. Birds nesting on trees without harming them |
Answer:
A – 3, B – 2, C – 4, D – 1
| Column I | Column II |
| A. Mutualism | 3. Bird eating pests from buffalo’s back |
| B. Parasitism | 2. Tick feeding on a cow |
| C. Commensalism | 4. Birds nesting on trees without harming them |
| D. Competition | 1. Two tigers fighting for territory |
Question 3.
Match the items in column I with column II.
| Column I | Column II |
| A. Bees pollinating flowers | 1. Predation |
| B. Lion hunting a zebra | 2. Mutualism |
| C. Tapeworm in a dog | 3. Commensalism |
| D. Barnacles on a whale | 4. Parasitism |
Answer:
A – 2, B – 1, C – 4, D – 3
| Column I | Column II |
| A. Bees pollinating flowers | 2. Mutualism |
| B. Lion hunting a zebra | 1. Predation |
| C. Tapeworm in a dog | 4. Parasitism |
| D. Barnacles on a whale | 3. Commensalism |