Answer: B

Explanation:

Soil erosion has become a serious problem for Indian agriculture. Its side effects are visible in other areas also. Accumulation of eroded materials in river valleys reduces their water carrying capacity. This often causes floods and damages agricultural land. Deforestation is one of the major causes of soil erosion. The roots of plants prevent erosion by holding the soil together. By dropping leaves and twigs they increase the amount of humus in the soil. In fact, there has been destruction of forests all over India but its impact on soil erosion has been greater in the hilly parts of the country. A large part of the cultivable land in the irrigated areas of India is becoming saline due to the effect of excessive irrigation. The salt accumulated in the lower layers of the soil comes to the surface and destroys the fertility. Chemical fertilizers are also harmful for the soil. Unless the soil receives sufficient humus, the chemicals make it hard and in the long run its fertility decreases. Hence, option (b) is the correct answer.

Answer: C

Explanation:

Earthquake is the most unpredictable and destructive natural disaster. The origin of earthquakes is related to tectonics. An earthquake is a sudden shaking of the Earth's surface, caused by energy generated by the movement of tectonic plates beneath the Earth's surface. These are destructive and affect wide areas. Earthquakes are caused by energy released from tectonic activities in the Earth's upper surface. In comparison, volcanic eruptions, rock falls, landslides, land subsidence (especially in mining areas), sinking of dams and reservoirs, etc. Hence, statements 1 and 2 both are correct.

Answer: B

Explanation:

Cyclones are large, rotating storms that form over warm, tropical oceans. They are characterized by low pressure, strong winds and heavy rainfall.

Anticyclones are large, rotating storms that form over land. They are characterized by high pressure, light winds and clear skies. Monsoons are seasonal winds that change direction with the seasons. They cause difference in temperature between land and ocean and cause rainfall. Hence, option (b) is the correct answer.

Answer: A

Explanation:

Nathu La Pass is a mountain pass located at an altitude of 4.310 meters in the Himalayas. It is located on the border of India and China, connecting Sikkim in India to Tibet in China. The port was closed after the India-China war of 1962, but was reopened for cross-border trade between the two countries in 2006. Nathu La Pass is an important trade route between India and China, and is also a popular tourist destination. Hence, pair 1 is not correctly matched.

Zojila Pass is a high altitude mountain pass located at an altitude of 3,528 meters in the western part of the Himalayas. It is located on the national highway, which connects Srinagar in Jammu and Kashmir to Leh in Ladakh. The pass is closed during the winter months due to heavy snowfall and avalanches. Zojila Pass is an important strategic location for India, as it provides access to the Siachen Glacier, the world's highest battlefield. Hence, pair 2 is not correctly matched.

Khyber Pass is a mountain pass located in the north-west of Pakistan at an altitude of 1,070 meters. It is located on the border of Pakistan and Afghanistan and is an important trade and transportation route between the two countries. The Daren has a long history of military conflicts, and has been an important route for invasions and conquests throughout history. Today, the Khyber Pass is a major tourist attraction, and it is also an important location for security forces due to the ongoing conflict in the area. Hence, pair 3 is correctly matched.

Answer: D

Explanation:

The Tropic of Cancer is an imaginary line drawn at 23°30' parallel to the Equator in the Northern Hemisphere. This line passes through 8 states of India. These states are Gujarat, Rajasthan, Madhya Pradesh, Chhattisgarh, Jharkhand, West Bengal, Tripura and Mizoram. Hence, option (d) is the correct answer.