26. Which one of the following is the correct sequence of ecosystems in the order of decreasing productivity?
a) Oceans, lakes, grasslands, mangroves
b) Mangroves, oceans, grasslands, lakes
c) Mangroves, grasslands, lakes, oceans
d) Oceans, mangroves, lakes, grasslands
Answer. c)
27. Contour bunding is a method of soil conservation used in
a) desert margins, liable to strong wind action
b) low flat plains, close to stream courses, liable to flooding
c) scrublands, liable to the spread of weed growth
d) None of the above
Answer: D)
28. Improper handling and storage of cereal grains and oilseeds result in the production of toxins known as aflatoxins which are not generally destroyed by the normal cooking process. Aflatoxins are produced by
a) bacteria
b) protozoa
c) Moulds
d) viruses
Answer. c)
29. Due to improper/indiscriminate disposal of old and used computers or their parts, which of the following are released into the environment as e-waste?
1. Beryllium
2. Cadmium
3. Chromium
4. Heptachlor
5. Mercury
6. Lead
7. Plutonium
Select the correct answer using the codes given below:
a) 1, 3, 4, 6 and 7 only
b) 1, 2, 3, 5, and 6 only
c) 2, 4, 5, and 7 only
d) 1, 2, 3, 4, 5, 6 and 7
Answer. B)
30. Acid rain is caused by the pollution of the environment by
a) carbon dioxide and nitrogen
b) carbon monoxide and carbon dioxide
c) ozone and carbon dioxide
d) nitrous oxide and sulfur dioxide
Answer. d)
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