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.

[EX Q]: Question: What are the light highlands of the moon called? Answer: terrae
[EX A]: The lunar surface has dark basalt maria. The light highlands are called terrae.

[EX Q]: Question: What do we call the seasonal movement of animals? Answer: migration
[EX A]: Monarch butterflies gather in large groups as they migrate 2,500 miles south each fall. They return to the north in the spring. This migration is a cycle that repeats every year.

[EX Q]: Question: What system consists of structures that produce eggs, secrete female sex hormones, and ultimately enable birth of a fetus? Answer: female reproductive system
[EX A]:
The female reproductive system consists of structures that produce eggs and secrete female sex hormones. They also provide a site for fertilization and enable the development and birth of a fetus.