In DNA replication . A. The two strands of DNA come apart.
B. A copy is made.
C. Each copy has one strand of "old" DNA and one strand of "new" DNA.
D. all of the above

you answer to this question is: D all of the above

the corpus luteum secretes estrogens and progesterone. the latter hormone causes changes in the uterus that make it more suitable for implantation of the fertilized ovum and the nourishment of the embryo. if the egg is not fertilized, the corpus luteum becomes inactive after 10–14 days, and menstruation occurs.

i hope this : )