71. Which of the following are different varieties of coal?
(i) Lignite
(ii) Bituminous coal
(iii) Anthracite
(iv) Magnetite
Options:
A. (i), (ii) and (iii) only
B. (i), (ii) and (iv) only
C. (ii) and (iii) only
D. (i), (ii), (iii) and (iv)
Answer:
Explanation:
72. Two statements are given below as Assertion (A) and Reason (R). Read them carefully and choose the correct option.
Assertion (A): Land degradation is a very serious problem in Punjab and Haryana.
Reason (R): Excessive use of fertilisers, pesticides, and irrigation water is common in these areas.
A. Both A and R are true and R is the correct explanation of A.
B. Both A and R are true but R is not the correct explanation of A.
C. A is true, but R is false.
D. A is false, but R is true.
Answer:
Explanation:
73. Which one of the following describes a system of agriculture in which a single crop is grown on a large area?
A. Shifting cultivation
B. Plantation agriculture
C. Subsistence agriculture
D. Mixed farming
Answer:
Explanation:
74. On which of the following rivers is the Koyna Dam built?
A. Krishna River
B. Godavari River
C. Narmada River
D. Tapi River
Answer:
Explanation:
75. Which of the following resources is used to produce hydroelectricity?
A. Water
B. Coal
C. Petroleum
D. Natural gas
Answer:
Explanation: