Peppered moths rest on tree trunks during the day. Birds eat peppered moths.
Peppered moths can be pale or dark. In the 1800s, smoke from factories covered the tree trunks in some areas with black soot.
The Figure shows a pale moth and a dark moth resting on a tree trunk covered with soot.
Figure

Use the Figure to explain which moth is more likely to be eaten by birds.
The dark colour is caused by an allele. State how this allele first arose.
Explain why the proportion of dark moths in these areas increased over many generations.
44 exam-style questions on Edexcel GCSE Biology 4.1 Evolution and natural selection, covering 4.1.1 Work of Darwin and Wallace and 4.1.2 Resistant organisms and evolution. Each one has a worked solution and a mark scheme showing where the marks go.