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

question:
Question: What types of glands do only female mammals have? Answer: mammary
answer:
Two traits are used to define the mammal class. They are fur or hair and mammary glands in females.

question:
Question: Where in relation to the home, are levels of vocs found to be higher? Answer: indoors
answer:
The processes of evolution are fundamental to much of biology. Why do people have such a hard time understanding them?.