John is studying animals.  What is one of the many things he has to watch them doing?
Options:
- bathe
- bite
- die of cancer
- obesity
- copulate
Please answer and provide answer explanation.

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Copulate means to have a sexual intercourse. Most animals have sexual intercourse to reproduce. The final answer: copulate.