Insecticides are chemicals used to control pest populations.
Name the main group of invertebrate animals targeted by insecticides.
Name the kingdom of organisms that naturally produce compounds such as nicotine or caffeine to defend against these animal pests.
Over time, some insecticides are no longer effective at controlling pest populations. Use your knowledge of natural selection to explain why.
44 exam-style questions on Edexcel IGCSE Biology Human influences on the environment. Each one has a worked solution and a mark scheme showing where the marks go.