A student measures the mass of dead leaves decomposed in 2 weeks at different temperatures.
Table
| Temperature in ∘C^\circ\text{C}∘C | 10 | 20 | 30 | 40 | 50 | 60 |
|---|---|---|---|---|---|---|
| Mass of leaves decomposed in g | 1.2 | 2.6 | 4.9 | 6.1 | 3.0 | 0.4 |
Which statement explains the change in the mass of leaves decomposed between 40 ∘C40\ ^\circ\text{C}40 ∘C and 60 ∘C60\ ^\circ\text{C}60 ∘C?
The decomposers have more kinetic energy, so they collide less often with the leaves.
The enzymes of the decomposers gain kinetic energy, so they bind the leaves more tightly.
The active sites of the decomposers' enzymes change shape, so fewer substrates can bind.
The decomposers respire aerobically more quickly, so they use up the leaves more slowly.
111 exam-style questions on OCR GCSE Biology 4.1 Ecosystems, covering 4.1.1 Cycling of materials in ecosystems, 4.1.2 Microorganisms in cycling materials, 4.1.3 The carbon and water cycles, 4.1.4 Factors affecting decomposition, 4.1.5 Levels of organisation in an ecosystem, 4.1.6 Abiotic and biotic factors affecting communities, 4.1.7 Interdependence and competition, 4.1.8 Trophic levels, 4.1.9 Pyramids of biomass, and 4.1.10 Efficiency of biomass transfers. Each one has a worked solution and a mark scheme showing where the marks go.