Identify 3 biotic factors and their roles in the economy

Role of Keystone Species in an Ecosystem. Earth Science, Ecology, Biology. A keystone species helps define an entire ecosystem.

Explanation:

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 : )