The evolution of exoskeleton in Arthropods is thought to have evolved in what manner?

Select one:
A. As the result of osmoregulatory cells in the epidermis of the skin

B. As the result of peromorphic changes in ontogeny of segmented worms

C. As the extension and modification of chitinous mouth parts in the anterior segment of segmented worms

D. As a modified radula from the Mollusca group

an active site is a region that is present on an enzyme where the reactants or the substrate molecules we can say bind and experience a chemical reaction. the substrate is basically a reactant whose concentration is changing and that is converting into a product after binding at the active site of an enzyme

the answer to your question is:

c. complementary base-pairing

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 : )