Equal samples of food are kept in sealed containers. Sample P is refrigerated. Sample Q is heated strongly, cooled and sealed without further contamination.
Which comparison explains how the treatments delay decomposition?
P kills microorganisms; Q only slows their enzyme activity.
P slows microbial enzyme activity; Q kills many microorganisms.
P removes water from microorganisms; Q removes their oxygen.
P removes oxygen from microorganisms; Q removes their water.
44 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.