Given a scientific question and its correct answer, generate supporting facts for the answer. This supporting fact can be an explanation for the answer to the given question.

Question: Producing sperm and secreting testosterone are the main functions of what system? Answer: male reproductive system
The main functions of the male reproductive system are to produce sperm and secrete testosterone.

Question: Most reptiles reproduce sexually and have what type of fertilization? Answer: internal
Most reptiles reproduce sexually and have internal fertilization.

Question: What unit of the nervous system consists of a cell body, dendrites, and axon? Answer: neuron
Neurons are the structural and functional units of the nervous system. They consist of a cell body, dendrites, and axon.