A student samples plants only beside a pond, where the soil is wetter than in the rest of a field. The student uses these results to estimate the number of plants in the whole field.
Which change would best improve the estimate?
sample at random coordinates throughout the whole field
repeat the counts in the same quadrats beside the pond
use smaller quadrats at the same points beside the pond
count a second plant species in quadrats beside the pond
39 exam-style questions on Edexcel GCSE Biology 9.1 Ecosystems and interdependence, covering 9.1.1 Levels of organisation in ecosystems, 9.1.2 Abiotic and biotic factors, 9.1.3 Importance of interdependence, 9.1.4 Parasitism and mutualism, and 9.1.5 Determining number of organisms in an area. Each one has a worked solution and a mark scheme showing where the marks go.