Biomagnification and Eutrophication MCQs and Answers

Are you looking for Biomagnification and Eutrophication MCQs and Answers for medical entrance examinations? If yes, these are some most important multiple choice questions and answers on NCERT Class-12 Biology, Chapter-16 (Environmental Issues).

Here we composed these Biomagnification and Eutrophication MCQs and Answers after reading the chapter on Environmental Issues from the NCERT book on Class 12 Biology. The questions are topics-wise and the students can relate the questions easily to the most important topics of this chapter.

Biomagnification and Eutrophication MCQs and Answers

1. Which of the following is the test to the determine amount of oxygen needed to oxidize all pollution materials?

a) Biological Oxygen Demand

b) Chemical Oxygen Demand

c) Botanical Oxygen Demand

d) Physical Oxygen Demand

Answer: b


2. How is the value of COD compared to BOD?

a) Much higher

b) Zero

c) Much lower

d) Low

Answer: a


3. What happens when phosphorus, nitrates, and detergents in water lead to an acceleration in the growth of algae?

a) Extinction

b) Eutrophication

c) Increase in the number of fishes

d) Increase in the number of aquatic plants

Answer: b


4. What happens when water is deoxygenated due to algal growth?

a) Increase in the number of fishes

b) Increase in the number of aquatic plants

c) Eutrophication

d) Death of aquatic animals

Answer: d


5. What is the increased productivity of ponds and lakes due to excess nutrients called?

a) Bio-magnification

b) Extinction

c) Eutrophication

d) Deforestation

Answer: c


6. What is the reason for the reduction in dissolved oxygen?

a) Bio-magnification

b) Eutrophication

c) Extinction

d) Pollution

Answer: b


7. When do the planktonic algae utilize oxygen?

a) Day

b) Afternoon

c) Evening

d) Night

Answer: d


8. What is the reason for choking of the surface off any pond or lake?

a) Nutrients

b) Fecal matter

c) Algal bloom

d) Bacteria

Answer: c


9. What phenomenon occurs due to the accumulation of certain pollutants that increase in concentration along the food chain?

a) Eutrophication

b) Pollution

c) Deforestation

d) Bio-magnification

Answer: d


10. Which of the following is an example of pollutants whose concentration increases in each trophic level?

a) Potassium

b) Glucose

c) DDT

d) Nitrogen

Answer: c


11. What happens to the concentration of DDT in each trophic level?

a) Decrease

b) Increases

c) Remains unchanged

d) Becomes zero

Answer: b


12. Which of the following is a primary treatment for water pollution?

a) Sludge method

b) Trickling filter method

c) Sedimentation

d) Removal of nitrates

Answer: c


13. Which of the following is a secondary treatment for water pollution?

a) Sedimentation

b) By the action of microbes

c) Removal of nitrates

d) Filtration

Answer: b


14. What happens in the tertiary treatment for water pollution?

a) Sedimentation

b) Filtration

c) Sludge method

d) Removal of nitrates, phosphates

Answer: d


15. What is the acceleration in the natural aging process of the lake due to the release of effluents from the industries called?

a) Accelerated Eutrophication

b) Eutrophication

c) Sedimentation

d) Bioamplification

Answer: a


FAQs on Biomagnification and Eutrophication

What is biomagnification?

Biomagnification is the process by which pollutants become more concentrated as they move up the food chain. This can happen when pollutants accumulate in the tissues of plants and animals, or when animals eat contaminated plants or prey. Over time, the concentration of the pollutant can become very high in the top predators of the food chain.

What is eutrophication?

Eutrophication is the process by which a body of water becomes overly enriched with nutrients. This can lead to an increase in the growth of aquatic plants and algae, which can suffocate other organisms and lead to changes in the water’s chemistry. Eutrophication is often caused by the discharge of sewage and other wastes into waterways. It can also be caused by the runoff of fertilizers and other chemicals from agricultural land.

What are the effects of biomagnification and eutrophication?

The effects of biomagnification and eutrophication can be very harmful to the environment. Biomagnification can lead to the build-up of toxins in the food chain, which can eventually contaminate the food we eat. Eutrophication can cause the depletion of oxygen in water, leading to the death of fish and other aquatic creatures. It can also make water unsafe for human use and lead to the growth of harmful algae blooms.

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