Alkali, or alkaline, soils are clay soils with high pH(>8.5), a poor soil structure and a low infiltration capacity. Often they have a hard calcareous layer at 0.5 to 1 metre depth. Alkali soils owe their unfavorable physico-chemical properties mainly to the dominating presence of sodium carbonate which causes the soil to swell and difficult to clarify/settle.

Correct Option: A

Alkali, or alkaline, soils are clay soils with high pH(>8.5), a poor soil structure and a low infiltration capacity. Often they have a hard calcareous layer at 0.5 to 1 metre depth. Alkali soils owe their unfavorable physico-chemical properties mainly to the dominating presence of sodium carbonate which causes the soil to swell and difficult to clarify/settle.

Black soil is a rich soil that is good for crops like cotton. It is found in various places around the world. It is most abundantly found in western central India.

Correct Option: B

Black soil is a rich soil that is good for crops like cotton. It is found in various places around the world. It is most abundantly found in western central India.

The Luni is a river of western Rajasthan state, India. It originates in the Pushkar valley of the Aravalli Range, near Ajmer and ends in the marshy lands of Rann of Kutch in Gujarat, after travelling a distance of 495 km.

Correct Option: A

The Luni is a river of western Rajasthan state, India. It originates in the Pushkar valley of the Aravalli Range, near Ajmer and ends in the marshy lands of Rann of Kutch in Gujarat, after travelling a distance of 495 km.

About 1,800 miles (2,900 km) long, the Brahmaputra is an important river for irrigation and transportation. The average depth of the river is 124 feet (38 m) and maximum depth is 380 feet (120 m). The river is prone to catastrophic flooding in spring when the Himalayan snows melt.

Correct Option: A

About 1,800 miles (2,900 km) long, the Brahmaputra is an important river for irrigation and transportation. The average depth of the river is 124 feet (38 m) and maximum depth is 380 feet (120 m). The river is prone to catastrophic flooding in spring when the Himalayan snows melt.

The Narmada, also called the Rewa, is a river in central India and the fifth longest river in the Indian subcontinent. It is the third longest river that flows entirely within India, after the Godavari and the Krishna.

Correct Option: B

The Narmada, also called the Rewa, is a river in central India and the fifth longest river in the Indian subcontinent. It is the third longest river that flows entirely within India, after the Godavari and the Krishna.