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GeographyMediumAsked in: NDA · NDA-II 2023, GAT

Which one of the following is an organic soil ?

  1. A.Aridisols
  2. B.Histosols
  3. C.Oxisols
  4. D.Vertisols

Correct answer

B. Histosols

Explanation

The correct answer is B, Histosols. Histosols are the soil order made mostly of organic matter, such as peat and muck, rather than of mineral particles.

In the USDA soil classification, Histosols form where waterlogging slows the decay of plant remains, so thick layers of partly decomposed material build up. They are found in bogs, marshes and swamps, and in India peaty soils of this kind occur in parts of Kerala, the Sundarbans and other waterlogged coastal tracts. The name comes from the Greek word histos, meaning tissue, a reminder that the soil is built from plant tissue.

A is wrong because Aridisols are dry mineral soils of deserts, very low in organic matter. C is wrong because Oxisols are deeply weathered, iron- and aluminium-rich mineral soils of the humid tropics. D is wrong because Vertisols are clay-rich mineral soils that swell and crack, like the black cotton soil of the Deccan.

Exam tip: Histosols are organic (peat), Vertisols are cracking black clays, Aridisols are desert soils, Oxisols are tropical laterite-type soils.

Practice Questions

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Q2.GeographyAsked in: CDS · CDS-II 2017, GKMedium

Which of the following statements is/are correct? 1. Himalayan rivers have their origin in the snow-covered areas, hence are dry in winter season. 2. Rivers of the Peninsular Plateau have reached maturity. 3. Himalayan rivers depict all the three stages of normal cycle of erosion. Select the correct answer using the code given below.

  1. A.2 only
  2. B.1 and 3 only
  3. C.2 and 3 only
  4. D.1, 2 and 3
Show answer
Correct answer: C. 2 and 3 only

Himalayan rivers are perennial, so statement 1 is wrong, while statements 2 and 3 are correct. Himalayan rivers such as the Ganga, Indus and Brahmaputra rise from glaciers and snowfields and also get monsoon rain, so they flow all year round, including in winter.

Q3.GeographyAsked in: CDS · CDS-II 2017, GKMedium

Which of the following statements related to latitude are true? 1. Rainfall, temperature and vegetation vary with latitude. 2. The difference between the longest day and the shortest day increases with latitude. 3. Indira Point is located approximately at 6°45' N latitude. Select the correct answer using the code given below.

  1. A.1 and 2 only
  2. B.1 and 3 only
  3. C.2 and 3 only
  4. D.1, 2 and 3
Show answer
Correct answer: D. 1, 2 and 3

All three statements about latitude are true. Latitude decides how directly the Sun's rays strike a place, so temperature, rainfall and the type of vegetation change from the equator towards the poles, from hot, wet rainforests to cold tundra.

Q4.GeographyAsked in: CDS · CDS-II 2017, GKMedium

Which of the following lakes is/are situated in Ladakh? 1. Tso Kar 2. Pangong Tso 3. Tsomgo 4. Tso Moriri Select the correct answer using the code given below.

  1. A.1 only
  2. B.2 and 3
  3. C.1, 2 and 4
  4. D.2 and 4 only
Show answer
Correct answer: C. 1, 2 and 4

Tso Kar, Pangong Tso and Tso Moriri are high-altitude lakes of Ladakh, while Tsomgo lies in Sikkim. Pangong Tso, at about 4,350 metres, is a long, narrow lake that stretches from Ladakh into Tibet, and most of its length lies on the Chinese side.