Scientists often use homology to support the theory of evolution.
Homology is the study of similar structures in different animals. For instance the forelimbs, or arms, of humans are similar to the forelimbs of apes, monkeys, most other mammals, birds, etc. Also the human eye is very similar to the eyes in other vertebrates. The creationist maintains that similar structures exist in different animals because God, the Master Engineer, created similar structures for similar needs. We see this in human engineering.