Access Class 8 Science Chapter 12 How Nature Works in Harmony Question Answer
All the answers given below are carefully prepared by the subject experts. These solutions are best for doing homework and revision easily and quickly. By reading the Class 8 Science Chapter 12 How Nature Works in Harmony question answer, students can understand how living and non-living things interact with each other.
Question 1: Refer to the given diagram and select the wrong statement.

(i) A community is larger than a population.
(ii) A community is smaller than an ecosystem.
(iii) An ecosystem is part of a community
Answer: The correct answer is option (iii), An ecosystem is part of a community
Explanation: According to the diagram, the population is a part of a community, and the community is a part of an ecosystem. So, the ecosystem is the largest unit, and the ecosystem is not a part of the community. Hence, option (iii) is wrong.
Question 2: A population is part of a community. If all decomposers suddenly disappeared from a forest ecosystem, what changes do you think would occur? Explain why decomposers are essential.
Answer: If all decomposers suddenly disappeared from a forest ecosystem, the following changes would occur.
Dead plants and animals will get collected because there will be no microorganisms to break them down.
Nutrients will not return to the soil, which makes the soil less fertile. Due to this, it becomes difficult to grow crops.
The complete ecosystem will get disturbed, and because of this, the survival of many organisms becomes difficult.
Question 3: Selvam from Cuddalore district, Tamil Nadu, shared that his village was less affected by the 2004 Tsunami compared to nearby villages due to the presence of mangrove forests. This surprised Sarita, Shabnam, and Shijo. They wondered if mangroves were protecting the village. Can you help them understand this?
Answer: Yes, mangrove forests played an important role in protecting Selvam’s village from the Cuddalore district during the 2004 tsunami. Mangroves have thick roots that slow down the strong winds and waves during storms and floods. When a tsunami happens, mangroves act as natural barriers that reduce the speed of waves, which lowers the damage.
Question 4: Look at this food chain:

If frogs disappear from this ecosystem, what will happen to the population of grasshoppers and snakes? Why?
Answer: If frogs disappear from the ecosystem shown above, then the complete food chain will be disturbed:
The grasshopper population will increase because no frogs are left to eat the grasshoppers.
Snake population will decrease because snakes depend on the frogs for food. And if no frogs are left, then no food is left for the snakes to eat.
This happens because every organism in a food chain is important and plays a major role. And if one is removed from it, it affects the complete food chain.
Question 5: In a school garden, students noticed fewer butterflies the previous season. What could be the possible reasons? What steps can students take to have more butterflies on campus?
Answer: The possible reasons for fewer butterflies in this season could be:
Less growth of flowering plants that provide nectar.
More use of chemical fertilizers can cause harm to butterflies and caterpillars.
Change of weather conditions and an increase in pollution can also affect the number of butterflies.
Steps which students can take to have more butterflies on campus are:
They can grow more flowering plants that are rich in nectar.
Some host plants can also be grown for caterpillars.
Use less chemical fertilizers in the garden.
Students can try to keep the garden clean and green to attract more butterflies.
Question 6: Why is it not possible to have an ecosystem with only producers and no consumers or decomposers?
Answer: It is not possible to have an ecosystem with only producers and no consumers and decomposers because:
Producers like plants produce food with the help of sunlight, but they need consumers to use that energy and food. Consumers are needed for the energy transfer in the food chain.
Decomposers like fungi and bacteria break down the dead plants and animals. These nutrients return to the soil, which then helps the plants to grow.
Question 7: Observe two different places near your home or school (e.g., a park and a roadside). List the living and non-living components you see. How are the two ecosystems different?
Answer:
Place | Park | Roadside |
Component Type |
|
|
Living | Trees, grass, flowers, butterflies, birds, squirrels, ants, insects | Few trees, small plants, stray dogs, crows, and insects |
Non-living | Soil, water, sunlight, air, rocks, and benches | Concrete, dust, vehicles, sunlight, air, garbage |
Differences between park and roadside:
The park has more plants and animals in comparison to the roadside.
The roadside has less greenery and more pollution, whereas the park has less pollution and fresh air.
Question 8: ‘Human-made ecosystems like agricultural fields are necessary, but they must be made sustainable.’ Comment on the statement
Answer: Human-made ecosystems like agricultural fields are necessary because they provide us with food. However, nowadays, the farming methods are considered unsustainable because of the overuse of chemical fertilisers, excessive groundwater extraction, and growing only one type of crop for commercial use. To make these ecosystems sustainable, we must use some natural methods like organic farming, crop rotation, etc. This helps protect soil nutrients, water, and biodiversity for future use.
Question 9: If the Indian hare population drops because of a disease, how would it affect the number of other organisms?

Answer: If the Indian hare population drops because of a disease, it will affect the entire food chain:
Foxes primarily feed on Indian hares, so their population will decline if hares disappear.
Grass and plants will increase slightly, as hares were eating the plants.
Also, check the NCERT Books and the NCERT Syllabus here
Important Questions from NCERT Class 8 Science Chapter 12 How Nature Works in Harmony
Solving questions like the one given below helps students understand the chapter better. To score well in exams, it’s good to solve different types of questions. For this purpose, students can depend on the NCERT Solutions for Class 8 Science Chapter 12 How Nature Works in Harmony, which makes learning easier.
Question 1: Which of the following microorganisms helps in the decomposition of dead plants and animals?
Options
- Algae
- Fungi
- Protozoa
- Viruses
Answer: The correct answer is option (2), Fungi
Explanation: Fungi are known as decomposers. They secrete enzymes that break down dead organic matter, recycling nutrients back into the ecosystem.
Question 2: In a food chain, which of the following is usually eaten first?
Options:
- Herbivores
- Carnivores
- Producers
- Decomposers
Answer: The correct answer is option (3), Producers
Explanation: Producers like plants make their own food through photosynthesis and are eaten by herbivores, forming the first step in a food chain.
Question 3: Which of these is a non-living component in an ecosystem?
Options:
- Plants
- Water
- Animals
- Fungi
Answer: The correct answer is option (2), Water
Explanation: Non-living components like water, sunlight, air, and soil support living organisms but do not have life themselves.
Question 4: The interaction between biotic and abiotic components in an area forms:
Options:
- Food chain
- Community
- Ecosystem
- Population
Answer: The correct answer is option (3), Ecosystem
Explanation: An ecosystem is formed when living organisms (biotic components) interact with non-living things (abiotic components) like water, soil, and sunlight. This interaction helps maintain balance in nature.
Question 5: Which of the following is an example of a terrestrial ecosystem?
Options:
- Ocean
- Desert
- Pond
- Lake
Answer: The correct answer is option (2), Desert
Explanation: Terrestrial ecosystems are land-based, such as forests, grasslands, and deserts, where organisms adapt to life on land. Aquatic ecosystems, like ponds and oceans, are water-based.