Question: When you compare G2 and prophase, I would think that both phases contain....(cont)?
the same amount of genetic material. Suggest what is or is not occurring once mitosis starts.  Edit

Answer: During the S period of interphase, the DNA duplicates and thus the quantity of genetic material increases from 2n to 4n. During G2, the quantity remains constant: 4n. After completion of mitotic phase the quantity of genetic material reduces to 2n in each daughter cell. The reduction in genetic material actually occurs during telophase.

When you compare G2 and prophase, I would think that both phases contain the same amount of genetic material.  Edit