Question

Embryo sac with zygote and primary endosperm nucleus

Answer 1

Endosperm is a tissue produced inside the seeds of most of the flowering plants following fertilization. It surrounds the embryo and provides nutrition in the form of starch, though it can also contain oils and protein. This can make endosperm a source of nutrition in the human diet. For example, wheat endosperm is ground into flour for bread (the rest of the grain is included as well in whole wheat flour), while barley endosperm is the main source of sugars for beer production. Other examples of endosperm that forms the bulk of the edible portion are coconut "meat" and coconut "water", and corn. Some plants, such as orchids, lack endosperm in their seeds.

Answer 2

In side Embryo sac the two male gamates enter through the pollen tube.One fuses with the egg to form zygote and process is called syngamy.The other fuses with the two polar nuclei to form Primary endosperm nucleus.This PEN further develops in to endosperm then the formation of embryo is iniated.