Exercise 1 — IGCSE 0653 May/Jun 2024 Paper 32 Q6
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0.0089 3600 1000
Cambridge IGCSE·Combined Sciences 0653·Physics
Organisms Environment
Key knowledge — Organisms Environment
Formulas & equations
Energy efficiency between trophic levels ≈ 10% (only ~10% of energy passes to next level)Population change = (births + immigration) − (deaths + emigration)
Key facts & rules
- Producer: photosynthetic organism (plant/algae) — first trophic level.
- Consumer: organism that eats other organisms.
- Decomposer: breaks down dead organic matter (bacteria, fungi) — recycles nutrients.
- Food chain: linear energy flow. Food web: interconnected food chains.
- Carbon cycle: photosynthesis removes CO₂; respiration, decomposition, combustion release CO₂.
- Nitrogen cycle: nitrogen fixation (bacteria) → nitrification → assimilation → denitrification.
- Limiting factors for population: food, water, space, predation, disease.
- Biodiversity: variety of species in an ecosystem — higher = more stable.
IGCSE Physics — Organisms & Environment
6 Cambridge IGCSE 0653 Combined Sciences past paper questions on organisms & environment, across Theory, Multiple Choice and Alternative to Practical.
Theory
Organisms & Environment — Core4 · Paper 3
Exercise 2 — IGCSE 0653 May/Jun 2025 Paper 33 Q3
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producer
Exercise 3 — IGCSE 0653 Oct/Nov 2023 Paper 32 Q3
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evidence of, W = mg / 2500 10
Exercise 4 — IGCSE 0653 Oct/Nov 2023 Paper 33 Q3
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evidence of, W = mg / 2500 10
Organisms & Environment — Extended2 · Paper 4
Exercise 1 — IGCSE 0653 May/Jun 2023 Paper 41 Q3
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radiation
Exercise 2 — IGCSE 0653 Oct/Nov 2023 Paper 42 Q3
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50 (s)
All Organisms & Environment questions in this collection
| Type | Level | Paper | Session | Q# | Marks | Answer / key |
|---|---|---|---|---|---|---|
| Theory | Core | Paper 32 | May/Jun 2024 | Q6 | 9 marks | 0.0089 3600 1000 |
| Theory | Core | Paper 33 | May/Jun 2025 | Q3 | 7 marks | producer |
| Theory | Core | Paper 32 | Oct/Nov 2023 | Q3 | 11 marks | evidence of, W = mg / 2500 10 |
| Theory | Core | Paper 33 | Oct/Nov 2023 | Q3 | 11 marks | evidence of, W = mg / 2500 10 |
| Theory | Extended | Paper 41 | May/Jun 2023 | Q3 | 9 marks | radiation |
| Theory | Extended | Paper 42 | Oct/Nov 2023 | Q3 | 11 marks | 50 (s) |