At divergent boundaries, what fills in the spaces as the plates pull apart?

assuming this is plate tectonics: At divergent boundaries where the plates pull apart, magma from the earth's mantle fills in the spaces created.

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 : )