What observations did Charles Darwin make about finches in the Galápagos Islands?

The galapagos island contain 13 species of finches four of the species are seen here it is believed that all of the species had one common ancestor and overtime

When a population split into two subgroups what is most likely to cause the subgroups to develop different traits?

Which of the following would involve looking at different structures of organisms and comparing how similar they are? a. vestigial structuresb. radiometric datingc. homologous structures