A student compares lichen communities on similar trees at different distances from a factory.
Why should she identify the lichen species rather than record only the total lichen cover?
Lichen species differ in their tolerance of air pollution.
Lichen species all grow at the same rate at each location.
Lichen species all indicate the same level of air pollution.
Lichen species all absorb the same amount of air pollution.
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.