Read the following descriptions of structures found in a mature typical angiosperm embryo sac: X : A group of three cells situated at the micropylar end. Y : Special cellular thickenings present at the micropylar tip of the synergids. Z : The largest cell of the embryo sac situated below the egg apparatus. Identify X, Y, and Z correctly from the given options.

Step-by-step solution

In a typical mature angiosperm embryo sac, three cells are grouped together at the micropylar end to constitute the egg apparatus (X). The egg apparatus consists of two synergids and one egg cell. The synergids possess special cellular thickenings at their micropylar tip, which are known as the filiform apparatus (Y). These play an important role in guiding the pollen tubes into the synergid. The largest cell of the embryo sac is the central cell (Z), which is situated below the egg apparatus and contains the two p