Genetic drift can best be defined as
a.
the adaptation of a population due to environmental changes. os
b.
a change in the allelic frequency within a population due to random chance
c.
a change in the allelic frequency within a population due to differential reproductive success.
cess.
d.
the transfer of alleles from one breeding population to another.

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 : )

several tissues working together form an organ, and several organs together make up an organisms.

the group of cell that carries out special jobs are tissue.