In a peat bog, the soil is waterlogged.
Dead plants in a peat bog do not fully decay.
Which statement explains why?
Waterlogged soil has too much oxygen, so the decomposers' enzymes are denatured.
Waterlogged soil has little oxygen, so the decomposers cannot respire aerobically.
Waterlogged soil is too warm, so the decomposers respire anaerobically and die.
Waterlogged soil has no carbon dioxide, so the decomposers cannot photosynthesise.
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.