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9.3 Material cycles and decomposition

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Question 36
H

Two heaps contain the same mass of moist plant waste. Heap P is at 20 ∘C20\,^{\circ}\text{C}20∘C and is turned regularly. Heap Q is at 30 ∘C30\,^{\circ}\text{C}30∘C and is tightly compressed. Both temperatures are below the decomposers' optimum. Q decomposes more slowly than P.

Which explanation best accounts for this result?

[1]
A

Compression increases oxygen supply enough to outweigh the effect of lower temperature.

B

Compression decreases oxygen supply enough to outweigh the effect of lower temperature.

C

Compression decreases oxygen supply enough to outweigh the effect of higher temperature.

D

Compression increases oxygen supply enough to outweigh the effect of higher temperature.

Markscheme

9.3 Material cycles and decomposition Questions

  1. GCSE
  2. /Biology
  3. /9.3 Material cycles and decomposition

101 exam-style questions on Edexcel GCSE Biology 9.3 Material cycles and decomposition, covering 9.3.1 Cycling of materials through ecosystems, 9.3.2 The carbon cycle, 9.3.3 The water cycle, 9.3.4 The nitrogen cycle, 9.3.5 Indicator species and pollution, 9.3.6 Decomposition in preservation and composting, and 9.3.7 Rate changes in decay of biological material. Each one has a worked solution and a mark scheme showing where the marks go.

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