Prelims · Geography · 19 questions

Earth, landforms & geomorphology

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Prelims 2021 · Q62

Easy

With reference to the water on the planet Earth, consider the following statements:

1.The amount of water in the rivers and lakes is more than the amount of groundwater.
2.The amount of water in polar ice caps and glaciers is more than the amount of groundwater.

Which of the statements given above is/are correct?

Answer & explanation

Answer: (b) 2 only

Only statement 2 is correct: ice caps and glaciers hold about 2 per cent of Earth's water, well above the 0.68 per cent held as groundwater, while rivers and lakes together hold only about 0.009 per cent.

✗ 1. NCERT's table gives fresh water lakes 0.009 per cent and rivers 0.0001 per cent of all water, far less than groundwater at 0.68 per cent.
✓ 2. The same table gives ice caps 2.0 per cent (glaciers are counted with them), which is roughly three times the groundwater share of 0.68 per cent.

Remember · Earth's water: oceans 97.3%, ice caps and glaciers 2.0%, groundwater 0.68%, lakes 0.009%, atmosphere 0.0019%, rivers 0.0001%.

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). Permalink ·

Prelims 2021 · Q64

Easy

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

Answer & explanation

Answer: (b) fissure volcanic rock

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

NCERT Class 10 · Contemporary India – II, Chapter 1 “This type of soil is typical of the Deccan trap (Basalt) region spread over northwest Deccan plateau and is made up of lava flows.”
NCERT Class 11 · Fundamentals of Physical Geography, Chapter 3 “The Deccan Traps from India, presently covering most of the Maharashtra plateau, are a much larger flood basalt province.”
NCERT Class 10 · Contemporary India – II, Chapter 1 “Red soil develops on crystalline igneous rocks in areas of low rainfall in the eastern and southern parts of the Deccan plateau.”

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). Permalink ·

The same topic in Mains

World physical geographyGS 1 syllabus
Geophysical phenomena & changing featuresGS 1 syllabus

Read it in NCERT

Class 10 Contemporary India – II, Chapter 1cited in 2 explanations
Class 11 Fundamentals of Physical Geography, Chapter 3cited in 1 explanation