1. The need for and the production are two characteristics of living things. 2. Many of the cell’s organelles have folds in order to maximize (2 words).

3. Cell theory states that all cells come from cells.

the answer is "a.) well–developed vascular system."

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 : )

69 is the correct math for the amino acids