AP BIOLOGY

Detailed explanation-1: -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: -Megasporogenesis refers to the development of megaspores from the megasporocyte, the cell that undergoes meiosis. Meiosis of the megasporocyte nucleus results in the formation of four haploid megaspore nuclei. In most taxa, meiosis is followed by cytokinesis, resulting in four megaspore cells.

Detailed explanation-3: -After meiosis of megaspore mother cell and forming an arrayed tetrad in a line (Plate I-3), three megaspores degenerated one by one from the micropyle end. In the process of degeneration, the numbers of calcium granules decreased in the three megaspores.

Detailed explanation-4: -The megaspore mother cell undergoes meiosis and forms four megaspores.