Of the three methods, two involve transmitting an extracellular stimulus through membrane bound proteins or receptors. an extracellular stimulus could interact with a membrane-bound protein and directly initiate a metabolic change through a within the cell.
a) true
b) false

answer; polycythemia is the correct answer;

the form of energy changes and the total energy increases0l

the answer is c.) there is a warm front in region a and a stationary front in region b.

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 : )