Answer:
1. The skeletons of mammals that existed 150 million years ago are different from the skeletons of mammals that exist today. Fossil record.
2. The front limbs of humans, bats, birds, and whales all have a similar bone structure. Comparative Anatomy.
3. All vertebrates contain the protein hemoglobin, but the structure of the hemoglobin molecule varies from one species to the next. Molecular evidence.