The megagametophyte of angiosperms is comprised of 7 cells, but 8 nuclei. How many rounds of mitotic cell division does the megaspore undergo to produce the megagametophyte?.

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.

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answer: substrate concentration. enzymes work best when there is a high enough substrate concentration for the reaction they catalyse.