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Prelims 2021 paper

UPSC CSE Prelims 2021 · GS Paper I · Question 64 · India: climate, soils & vegetation

भारत में काली कपास मृदा की रचना, निम्नलिखित में से किसके अपक्षयण से हुई है?

UPSC Civil Services (Preliminary) Examination 2021, General Studies Paper I, Question 64 — India: climate, soils & vegetation.

Prelims 2021 · Q64

India: climate, soils & vegetation Easy

भारत में काली कपास मृदा की रचना, निम्नलिखित में से किसके अपक्षयण से हुई है?

Read this question in English

The black cotton soil of India has been formed due to the weathering of

(a) brown forest soil · (b) fissure volcanic rock · (c) granite and schist · (d) shale and limestone

उत्तर और व्याख्या · explanation in English

Answer: (b) विदरी (फिशर) ज्वालामुखीय चट्टान

Black cotton soil (regur) forms from the weathering of the basalt lava that poured out of fissures to make the Deccan Traps, so the parent rock is fissure volcanic rock.

  • ✓ (b) NCERT calls black soil typical of the Deccan trap (basalt) region and says it is made up of lava flows. The Deccan Traps are a flood basalt province built by lava outpourings through cracks in the crust.
  • ✗ (c) Granite and schist are crystalline rocks; NCERT links red soil, not black soil, with crystalline igneous rocks on the Deccan plateau.
  • ✗ (a) Brown forest soil is itself a soil, not a rock, so it cannot be the rock whose weathering produces black soil.
  • ✗ (d) Shale and limestone are sedimentary rocks; black soil forms from volcanic basalt.

Remember · Black (regur) soil comes from Deccan Trap basalt, which erupted from fissures; it holds moisture well and suits cotton.

📘 Read it in NCERT: Class 10 Contemporary India – II, Ch 1 (practise this chapter) · Class 11 Fundamentals of Physical Geography, Ch 3 (practise this chapter) · Class 10 Contemporary India – II, Ch 1 (practise this chapter)

Sources

Question and answer: UPSC's official GS Paper I (2021, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·

Cite this question: UPSC CSE Prelims 2021, Q64 — minimalistias.com/pyqs/prelims/2021/q64

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