Final answer:
During angiosperm germination, the generative cell becomes two sperm cells through mitosis as the pollen tube grows through the style. This typically occurs after pollination and results in double fertilization, whereby one sperm fertilizes the egg and the other the central cell, creating the endosperm.
Step-by-step explanation:
During angiosperm germination, the generative cell within the pollen grain divides to become sperm through a process that occurs after the pollen has been transferred to the stigma of a flower, namely during pollination. It is not until the pollen tube begins to grow and the pollen tube cell travels down through the style towards the ovule, that the generative cell divides by mitosis to form two sperm cells. This division usually happens as the pollen tube grows through the pistil's tissues. Once formed, these two sperm cells participate in double fertilization: one sperm cell fertilizes the egg, forming a diploid zygote, and the other fertilizes the central cell to create a triploid cell that will develop into the endosperm that nourishes the developing embryo.