A survey finds fewer insects of one species in woodland patches where a disease of this insect is more common. The food eaten by the insect is also less available in those patches.
Which conclusion is best supported by these results?
Disease, lower food availability or both could have reduced the number of insects.
Disease reduced the number of insects, because it was more common where insects were fewer.
Lower food availability could have reduced the number of insects, so disease probably had no effect.
Lower food availability reduced the number of insects, because insects need food to survive.
82 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.