Hypothesize why only one genus and species remains in the hominin group

There are two possible hypotheses behind one genus and species in the hominin group. All others have become extinct. The hypotheses are:

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 : )