when studying populations an ecologist must think about all of these population size population density or population desperation which one​

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 : )

d. planting trees

the trees take in carbon to make oxygen.

it is a limiting nutrient limited by a single nutrient in the ecosystem, & the single goes very slow.