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Topic Decomposition
Asked 3 times across 3 UPSC exams over 8 years (2017–2025), peaking in 2021.
Key insights
- Most tested in CSE — 1 of 3 PYQs
- First appeared in CDS 2017 — 4 years before CSE 2021 (allied exams preview CSE)
- Most asked in 2021
- Recurs across 3 years (2017–2025)
How it travelled across exams
First appearance in each exam — the same idea, reframed.
CDS 2017 → CSE 2021 → GEO 2025
How the concept evolved
Rising — more than half its appearances (3 of 3) are since 2016.
Related concepts
Ideas UPSC tests alongside this one — keep exploring.
Sample questions
You've seen the pattern — here are a few of the actual PYQs.
GEO2025
Which of the following organisms ingest dead organic matter and then digest internally and absorb the nutrients?
- A Detritivores only ✓
- B Saprotrophs only
- C Both detritivores and saprotrophs
- D Chemotrophs
✓ Correct answer: (A)
Science & Technology › Biology & Health
CSE2021
Which of the following are detritivores?
- Earthworms
- Jellyfish
- Millipedes
- Seahorses
- Woodlice
Select the correct answer using the code given below.
- A 1, 2 and 4 only
- B 2, 3, 4 and 5 only
- C 1, 3 and 5 only ✓
- D 1, 2, 3, 4 and 5
✓ Correct answer: (C)
Environment & Ecology › Ecology & Ecosystems
CDS2017
The foul smell of urine of a healthy man having healthy food, when spilled on floor, is mainly due to the bacterial decomposition of
- A urea into sulphur dioxide
- B sugar into carbon dioxide
- C lipids into methane
- D urea into ammonia ✓
✓ Correct answer: (D)
Science & Technology › Biology & Health
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