Pollution Control Questions and Answers – Effects of Pollution on Ecosystem – Set 2

This set of Pollution Control Multiple Choice Questions & Answers (MCQs) focuses on “Effects of Pollution on Ecosystem – Set 2”.

1. How does food pollution occur?
a) Biomagnification in the food chain
b) Water runoff from eroded soil
c) Pesticide absorption by the plants
d) Food adulteration during processing
View Answer

Answer: a
Explanation: Biomagnification causes food pollution. Producers absorb pollutants, then transfer them to consumers. These plants and animals are used as food by humans, who get contaminated as a result.

2. Which of the following is the cause of loss of biodiversity?
a) Biomagnification in the food chain
b) Water runoff from ecosystems
c) Resource availability for plants and animals
d) Habitat loss for plants and animals
View Answer

Answer: d
Explanation: Loss of habitat causes loss of biodiversity. It can occur due to exploitation of resources by humans, deforestation, conversion of forest areas to agricultural, residential, or industrial areas for human use.

3. What is the prime cause of the mass extinction of species in ecosystems?
a) Killing of animals by humans
b) Killing of plants by humans
c) Biodiversity loss
d) Deforestation
View Answer

Answer: c
Explanation: Biodiversity loss due to habitat loss causes the extinction of species in ecosystems. Plant and animal species get forced to either migrate from affected areas or die out if they are unable to migrate.

4. How does pollution, as a whole, affect food webs?
a) Food webs are lost in their entirety
b) It destabilises the food web
c) It does not affect the food webs
d) Food webs shift to other ecosystems
View Answer

Answer: b
Explanation: In ecosystems, problems caused by pollution destabilise the food web. For example, deforestation causes the large-scale migration of birds. Another example is mercury poisoning causing the death of fish. Such migration or death affects the prey and predators of birds and fish, leaving them without food.

5. Which of the following is NOT an air pollutant that affects ecosystems?
a) Ozone
b) Sulphur dioxide
c) Nitrogen dioxide
d) Hydrogen
View Answer

Answer: d
Explanation: Ozone, sulfur dioxide, and nitrogen dioxide are known to impact ecosystems either locally or regionally. They can alter plant productivity, acidify ecosystems, and cause eutrophication. On the other hand, hydrogen does not have negative impacts.

6. Which of the following energy production sources is directly responsible for the disruption of river ecosystems?
a) Hydroelectric power
b) Fossil fuels
c) Nuclear energy
d) Solar power
View Answer

Answer: a
Explanation: Hydroelectric power directly affects aquatic ecosystems. The hydroelectric power generation units are built on river systems, and hence, disrupt the natural processes of the river ecosystem. It can result in a drop in crop yields downstream of the dam. The other options have indirect effects.

7. Which process is responsible for the accumulation of mercury in the food web?
a) Oxidation of mercury metal
b) Chlorination of mercury metal
c) Methylation of mercury metal
d) Mercury is retained in its metallic form
View Answer

Answer: c
Explanation: Mercury gets accumulated in the food chains and food webs on account of its methylation. Mercury ions get attached to methyl groups in this process, which are stable compounds. This phenomenon is very prominent in aquatic ecosystems, but it is observed in forest ecosystems as well.

8. How does surplus nitrogen affect plants in ecosystems?
a) It decreases plant productivity
b) It changes plant composition
c) It increases plant productivity
d) It causes acidification of plants
View Answer

Answer: b
Explanation: Plant composition changes upon prolonged exposure to excess nitrogen in the soil. As a result, it becomes difficult to ascertain how this change of composition may affect the ecosystem in the future, and humans at large.

9. Which of the following does NOT lead to eutrophication in water bodies?
a) Algae growth in water bodies
b) Nitrogen saturation in the soil
c) Acidification of water bodies
d) Fertiliser runoff in the from cropland
View Answer

Answer: c
Explanation: Algae growth, nitrogen saturation, and fertiliser runoff all lead to eutrophication in water bodies. Eutrophication of water bodies, in turn, causes acidification of these water bodies.

10. Why are chlorinated hydrocarbons like aldrin hazardous?
a) They accumulate in the food chain
b) They are absorbed by plants
c) They kill too many pests
d) They cause water pollution
View Answer

Answer: a
Explanation: Pesticides like aldrin accumulate in the food chain on account of biomagnification. Since their concentration increases with trophic level, they are a threat to species that come in contact with them, including humans. Involuntary muscle actions and irritability are long-term effects of this pesticide on humans.

11. Which category of pollutants is the top contributor to ecosystem deterioration?
a) Air pollutants
b) Water pollutants
c) Food pollutants
d) Soil pollutants
View Answer

Answer: a
Explanation: Air pollutants have detrimental effects on ecosystems because they indirectly cause soil and water pollution. Air pollutants are directly absorbed by trees in forests. They also erode the soil due to acid rain. Then, water runoff displaces the soil into water bodies, successfully transferring pollutants through several ecosystems.

12. What happens if the secondary consumers in the following food chain go extinct?

a) Food chain gets disrupted
b) There is no change
c) Food web gets disrupted
d) Ecosystem is not affected
View Answer

Answer: a
Explanation: If the secondary consumers in the food chain go extinct, the food chain gets disrupted. There will be an excess of primary consumers, because of the extinction of its hunters. The tertiary consumers that prey on the primary consumers either migrate to another place or have to find other prey.

13. Which parts of trees are effected most by acid rain?
a) Leaves and roots of trees
b) Roots and bark of trees
c) Bark and leaves of trees
d) Fruit and bark of trees
View Answer

Answer: a
Explanation: Acid rain affects the roots and leaves of trees, that display the effects readily. Roots absorb the acid from the soil, while the leaves get discoloured from the acid. The overall plant productivity reduces as a result.

14. Which of the following is NOT an effect of noise pollution on wild animals?
a) It disrupts the communication of wild animals
b) It stresses wild animals
c) It makes wild animals deaf
d) It affects the behaviour of wild animals
View Answer

Answer: c
Explanation: Noise pollution can severely affect the quality of life of animals in the wild if these areas are close to human settlements or industries. They can hinder communication and stress animals out, but there has been no indication of these species becoming deaf.

15. How do air pollutants affect groundwater quality?
a) They affect plants that filter salts
b) They cause acidification of water bodies
c) They cause the acidification of soil
d) They prevent factories from purifying water
View Answer

Answer: a
Explanation: Air pollutants indirectly affect water quality by affecting flora. The roots of plants consume lots of nutrients, preventing them from reaching groundwater. When the plant roots are affected because of acidic soil conditions, they are unable to filter salts, hence, adversely affecting water quality.

Sanfoundry Global Education & Learning Series – Pollution Control.

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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