A student investigates how the abundance of a plant changes with distance from a hedge.
The student samples only patches where the plant is visible and records the light intensity in each patch.
Which replacement method would best address both the sampling bias and the investigation's aim?
Sample fixed intervals along several transects away from the hedge; record plant counts and light intensity at every position.
Sample randomly across the entire field; combine all plant counts and light intensities into one mean for the field.
Sample fixed intervals along several transects beside the hedge; record plant counts and light intensity at every position.
Sample randomly within patches containing the plant; record plant counts and light intensity at every selected position.
40 exam-style questions on AQA GCSE Biology 7.2 Organisation of an ecosystem, covering 7.2.1 Levels of organisation, 7.2.2 How materials are cycled, 7.2.3 Decomposition, and 7.2.4 Impact of environmental change (HT only). Each one has a worked solution and a mark scheme showing where the marks go.