Typical angiosperm embryo sac (8-nucleated, 7-celled) consists of: 1. Egg apparatus (3 cells = 2 synergids + 1 egg cell): Towards the micropylar end. 2. Antipodals (3 cells): Towards the chalazal end. 3. Large central cell (1 cell): It possesses 2 polar nuclei.
Embryo sac formed by haploid megaspore, therefore, before fertilization, has ploidy level as haploid.