"A male gametophyte is enclosed within the pollen wall of a pollen grain. Sporopollenin in the pollen wall protects the male gametophyte in the pollen grain as it is transported by wind or by hitchhiking on an animal. The transfer of pollen to the part of a seed plant that contains the ovules is called pollination. Following pollination, the male gametophyte develops a pollen tube that discharges sperm to fertilize the egg, which will develop into the sporophyte embryo.
a) The microsporangium is the structure of the sporophyte that produces the microspores that develop into the pollen grains.\
b) The megasporangium is the structure of the sporophyte that produces the megaspore.
c) Seed plants retain the megasporangium within the parent sporophyte, where it produces the megaspore. The whole structure of the megasporangium, megaspore, and their integument(s) is called an ovule.
d) Protected inside each ovule, a female gametophyte develops from the megaspore and produces one or more eggs."
