An investigation is carried out to determine how abiotic factors affect the rate of nutrient cycling by saprobionts in forest soils. Which row in the table shows the conditions that would result in the fastest rate of organic matter decomposition?
Soil Moisture StatusSoil Temperature (∘C)Soil pHAWaterlogged254.0BMoist (non-waterlogged)306.8CMoist (non-waterlogged)757.0DDry156.5 \begin{array}{|c|c|c|c|} \hline & \text{Soil Moisture Status} & \text{Soil Temperature } (^\circ\text{C}) & \text{Soil pH} \\ \hline \mathbf{A} & \text{Waterlogged} & 25 & 4.0 \\ \hline \mathbf{B} & \text{Moist (non-waterlogged)} & 30 & 6.8 \\ \hline \mathbf{C} & \text{Moist (non-waterlogged)} & 75 & 7.0 \\ \hline \mathbf{D} & \text{Dry} & 15 & 6.5 \\ \hline \end{array} ABCDSoil Moisture StatusWaterloggedMoist (non-waterlogged)Moist (non-waterlogged)DrySoil Temperature (∘C)25307515Soil pH4.06.87.06.5Row A
Row B
Row C
Row D
67 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.