$X$ – $MMC$ is a large cell containing dense cytoplasm and a prominent nucleus

$Y$ – Method of embryo sac formation from a single megaspore is termed monosporic

The formation of embryo sac is called

Choose correct sentence.

$(I)$ Nucleus of the functional megaspore divides meiotically to form two nuclei.

$(II)$ After $8$ nucleate stage, cell walls are laid down leading to organization of typical female gametophyte

$(III)$ The egg apparatus, consists of two synergids and one egg cell.

$(IV)$ Three cells are at the chalaza end are called antipodal cells.

Embryo sac consists of

A linear tetrad of $4$ cells lying in an axial row is formed during the development of