Q. What is embryonic sac? Which are the cells that form the embryonic sac? What are their ploidies?
The embryonic sac is female gametophyte of angiosperms.
The embryonic sac is collected of three cells that remain next to the micropyle, two lateral synergids and the central oosphere (egg); one binucleated cell, the polar nuclei, is placed in the central region; three antipodal cells stay in the opposite side to the micropyle. Ever since all these cells come by mitosis from the functional megaspore they are haploid (n).