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CSAT 2016 paper

UPSC CSE CSAT 2016 · Question 65 · Reading comprehension

Which among the following is the most logical assumption that can be made from the above passage?

Passage—2

All humans digest mother's milk as infants, but until cattle began being domesticated 10,000 years ago, children once weaned no longer needed to digest milk. As a result, they stopped making the enzyme lactase, which breaks down the sugar lactose into simple sugars. After humans began herding cattle, it became tremendously advantageous to digest milk, and lactose tolerance evolved independently among cattle herders in Europe, the middle East and Africa. Groups not dependant on cattle, such as the Chinese and Thai, remain lactose intolerant.

CSAT 2016 · Q65

Reading comprehension Medium

Which among the following is the most logical assumption that can be made from the above passage?

Answer & explanation

Answer: (b) A permanent change in the food habits of a community can bring about a genetic change in its members

Once herders began drinking milk as adults, lactose tolerance evolved among them, while groups not dependent on cattle stayed intolerant. The passage rests on the idea that a lasting change in a community's diet can bring about a genetic change in its members.

  • ✗ (a) Cattle domestication 10,000 years ago is stated in the passage — a given fact, not the assumption behind its argument.
  • ✓ (b) Lactose tolerance 'evolved' among herders after milk entered their diet; groups 'not dependant on cattle' remain intolerant.
  • ✗ (c) Lactase only breaks lactose into simple sugars; nothing says others cannot get simple sugars — 'only' is unsupported.
  • ✗ (d) 'Any dairy product' is too extreme; the passage speaks only of digesting milk sugar.

Remember · The best assumption links the passage's cause to its effect; options that repeat a stated fact or add 'only' or 'any' are weaker.

Question and answer: UPSC's official GS Paper II (2016, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·

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