NEET BIOLOGY

Detailed explanation-1: -The functional megaspore in angiosperm develops into an embryo sac. So, the option d) Embryo sac, is correct.

Detailed explanation-2: -Final answer: In an angiosperm, a functional megaspore develops into an embryo sac.

Detailed explanation-3: -Hint: In angiosperms, functional megaspore develops into a female gametophyte which is located in the nucellus. In plants, fertilization occurs in this location and forms the egg cell or nucleus developing into an embryo after fertilization.

Detailed explanation-4: -The megaspore mother cell undergoes meiosis to give rise to 4 haploid cells. Three haploid cells degenerate and one survives to become the embryo sac. The embryo sac enlarges in size and the haploid nucleus undergoes mitosis to form 2 haploid nuclei.

Detailed explanation-5: -An embryo sac is said to form when the haploid megaspore nucleus divides. It possesses two haploid nuclei and six haploid cells which do not have cell walls. In some cases, the haploid nuclei combine forming a single cell (endosperm motor cell).