Indicate the stages where meiosis and mitosis occur (1, 2 or 3 ) in the flow chart.
`"Megaspore mother cell"overset(1)rarr"Megaspores"overset(2)rarr"Embryo sac" overset(3)rarr"Egg"`

Explanation

`"Megaspore mother cell (2n)" overset("Meiosis")rarr"Megaspores" overset("Mitosis")rarr"Embroyo sac (n)"overset("Meiosis")rarr "Egg"`
The diploid Megaspore Mother Cell (MMC) undergo meiosis and forms a linear tetrad of four haploid megasporse. Three mitotic divisions , inside the functional (one) megaspor form the embryo sac (eight haploid nuclei), while the other three megaspores degenerate.
The embryo sac is a seven-celled and eight uncleated structure . Three microplar, Three chalazal and one central. The three micropylar cells are collectively known as egg-apparatus, which , consists of two synergids and one egg cell.
While three chalazal cell form antipodal cell. The central cell is in the form of two nucleated cell till the fertilisation occurs and called as polaar nuclei.