Scientists compare DNA base sequences from three organisms, A, B and C. All three have cells with a nucleus. The sequences from A and B are more similar to each other than either is to the sequence from C.
What does this evidence suggest about the evolutionary relationships of these organisms?
A, B and C are equally closely related because all three have cells with a nucleus.
A and B share an older common ancestor with each other than either shares with C.
A and B share a more recent common ancestor with each other than either shares with C.
C is more highly evolved than A and B because its DNA sequence is the most different.
85 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.