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NCERT Exemplar · Class 12 · Biology

Chapter 16: Environmental Issues

Practice each question, then open the answer or worked solution.

Multiple Choice Questions

22 questions
Q21Multiple choice

Match the items in column I and column II and choose the correct option:

Column I

Column II

a.

UV

i.

Biomagnification

b.

Biodegradable organic matter

ii.

Eutrophication

c.

DDT

iii.

Snow blindness

d.

Phosphates

iv.

BOD


The correct match is:

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Correct option: C
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Worked solution

Ans: Correct option is c

Excess exposure to UV light causes snow blindness or cloudy cornea in the eye. 

The decomposition of various biodegradable organic matter increases BOD (biological oxygen demand) of water. 

DDT is known to undergo biomagnification at various trophic levels in the food chain especially seen in predatory birds whereas phosphates accelerate the ageing of lakes by increasing the eutrophication rate. 

 

Q22Multiple choice

In the textbook you came across “Three Mile Island and Chernobyl disasters associated with accidental leakage of radioactive wastes." In India we have the Bhopal gas tragedy. It is associated with which of the following?

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Correct option: B
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Worked solution

Ans: Correct option is b

On the night of December 2-3, 1984, clouds of methyl isocyanide were formed in Bhopal, Madhya Pradesh all across the sky. From a pesticide plant in union carbide India limited, this chemical got leaked on that night. The gas was seen to have had various acute, short lasting and long-term effects on the human body. Acute effects included vomiting, suffocation and pulmonary edema while the genetic effects brought various harmful mutations that lead to genetic disorders.