Provide your best answer for the following question. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The question is: The forelimb of the monkey, bat, penguin, and alligator look very different on the outside, but their skeletal structures are similar. This evidence suggests that these animals
share a common ancestor.