Ans: A

Exp:

Black soils are found in the Deccan plateau and the valleys of the Narmada and Tapi rivers. They are characterised by a dark colour and are rich in potash and lime, with a well-drained and loamy texture. They are suitable for growing cotton, wheat, and pulses. Black soils are derivatives of trap lava and are spread mostly across interior Gujarat, Maharashtra, Karnataka, and Madhya Pradesh on the Deccan lava plateau and the Malwa Plateau, where there is both moderate rainfall and underlying basaltic rock.

Alluvial soils are found in the floodplains of rivers. They are characterised by their loose texture and high water-holding capacity. They are suitable for growing a variety of crops, including rice, wheat, and sugarcane.

Peaty soils are found in marshy areas. They are characterised by their high organic matter content and acidic pH. They are not suitable for most crops, but they can be used to grow cranberries and blueberries.

Laterite soils are found in tropical and subtropical regions. They are characterised by their high iron and aluminium content and low fertility. They are not suitable for most crops, but they can be used to grow cashew nuts and rubber.

Therefore, the black soils are the best description for the passage given above.

Ans: B

Exp:

Badlands are areas of land that are characterised by steep ravines and gullies. They are formed by the rapid erosion of soil and bedrock.

Statement 1 is incorrect: The sediment carried by the Chambal River is not likely to clog the soil. The sediment is mostly sand and gravel, which are relatively coarse materials. These materials are not likely to clog the soil and make it more susceptible to erosion.

Statement 2 is incorrect: The wind erosion in the Chambal Valley is not the main cause of the formation of badlands. As badlands are created by the erosion of the water.

Statement 3 is correct: The lack of vegetation with deep roots is the most appropriate factor. The badlands have scrub vegetation, which does not have deep roots. The vegetation helps to hold the soil in place and prevent it from eroding. Thus, a lack of vegetation with deeper roots leads to the loss of topsoil. This creates conditions suitable for erosion. When the rains come, the water washes away the soil and exposes the bedrock. This process is further accelerated by the presence of ravines and gullies, which provide channels for the water to flow at a rapid speed, aiding erosion.

Statement 4 is incorrect: Earthquakes are not a common occurrence in the Chambal Valley. The earthquakes that do occur are not strong enough to cause the soil to collapse and form gullies.

Ans: D

Exp:

Statement 1 is correct: Tropical thorn forests are found in areas with an annual rainfall of less than 70 centimetres. The rainfall pattern in these areas is characterised by a long dry season followed by a short wet season.

Statement 2 is correct: The trees in tropical thorn forests have adapted to this rainfall pattern by having thick, waxy leaves that help reduce water loss. The trees also have deep roots that can reach water stored in the soil during the dry season.

• Some of the common trees found in tropical thorn forests include acacia, baobab, and neem. These trees are all drought-tolerant and have adapted to the harsh conditions of the tropical thorn forest.

Statement 3 is correct: These forests consist of a variety of grasses and shrubs. This forest type is extensively distributed throughout the dry peninsular tract on the leeward side of the Western Ghats from south to north. It is important in Maharashtra, Andhra Pradesh, Karnataka, and Tamil Nadu. The type also occupies fairly large tracts over the semi-arid regions of Uttar Pradesh, Madhya Pradesh, and a major portion of the semi-arid and arid regions of Punjab, Haryana, Rajasthan, and north Gujarat including Saurashtra and Kutch.

Ans: D

Exp:

Statement 1 is correct:  Alpine areas are high-elevation ecosystems that occupy the higher reaches of mountains above the climatic tree line. Alpine vegetation is found in areas with an altitude of more than 3,600 metres above sea level. This is because the temperature at this altitude is too cold for most trees and shrubs to grow.

• Alpine vegetation is found in the mountains of many parts of the world, including the Himalayas, the Andes, and the Rockies.

Statement 2 is correct: This vegetation is characterised by short, stunted trees and shrubs that have adapted to the harsh climate. The short stature of these plants helps them to conserve heat and water. It is home to a variety of plant and animal species, including mountain goats, ibex, and pikas.

Statement 3  is correct: The trees in alpine vegetation have needle-like leaves that help to reduce water loss. The needle-like leaves have a small surface area, which reduces the amount of water that the plant loses through evaporation. Alpine vegetation is under threat from climate change and human activities, such as tourism and mining.

Ans: B

Exp:

Statement 1 is correct: In the Upper and Middle Ganga plains, distinct alluvial soil types have emerged, namely Khadar and Bhangar.

• Khadar, being the newer alluvium, results from annual flood depositions that enhance the soil with fine silt. Bhangar represents older alluvium deposited away from the floodplains.
• Both Khadar and Bhangar soils encompass calcareous concretions (Kankars). These soils demonstrate a higher content of loam and clay in the middle and lower Ganga plains as well as the Brahmaputra valley.

Statement 2 is incorrect: The nutrient composition of alluvial soils is characterised by a richness in potash but a deficiency in phosphorus. These soils cover about 40 percent of the total area of the country. They are depositional soils, transported and deposited by rivers and streams.

Statement 3 is incorrect: Soil particles are classified into three size groups: sand, silt, and clay. Sand particles are the largest, while clay particles are the smallest. Soil composition generally consists of a blend of these three components. Soil texture is determined by the relative proportions of sand, silt, and clay. For example, a clay loam texture signifies roughly equal quantities of sand, silt, and clay. These variations in texture are outcomes of the weathering process. Thus, Alluvial soils exhibit a spectrum of textures, ranging from sandy loam to clay. The sand content decreases progressively from the west to the east. Alluvial soils possess limited depth compared to the notable depth of black soils.