AP BIOLOGY

Detailed explanation-1: -From the remaining functional megaspore, the megagametophyte (also known as female gametophyte or embryo sac) develops by three mitotic divisions, at the mature stage consisting of 8 nuclei and 7 cells (one egg cell, two synergids, one central cell and three antipodals).

Detailed explanation-2: -Cells of the embryo sac divide by mitosis to give egg apparatus and accessory cells.

Detailed explanation-3: -Embryo sac develops from megaspore mother cell through. A. 1 meiosis and 2 mitosis.

Detailed explanation-4: -For the formation of 8 nucleated embryo sac, there occur three generations of free nuclear mitotic divisions.

Detailed explanation-5: -An embryo sac is said to form when the haploid megaspore nucleus divides. It possesses two haploid nuclei and six haploid cells which do not have cell walls. In some cases, the haploid nuclei combine forming a single cell (endosperm motor cell).