Certain chemicals, such as cytochrome C, are found within cells of all living organisms. The biochemical structure of cytochrome C in ground finches and in tree finches is very similar. This suggests that tree finches and ground finches have –

Common ancestor.

Explanation:

The similar biochemical structure of cytochrome C in ground finches and in tree finches indicates that they are evolved from a common ancestor. The evolution of finches into ground finches and tree finches occurs due to their environmental conditions which compel them to adopt certain physical features and behaviour that helps them in obtaining food and survival in their environment.

i think the miocene epoch spans the time from 23 million to 12 million years ago.

sorry, but you do not have posted the diagram.