Identify the correct sequence involved in the formation of female gam…

The correct answer is Option (3) → (B), (A), (D), (C)

(B) Functional megaspore — first. The megaspore mother cell divides by meiosis into four megaspores. Only one stays functional; the other three degenerate.

(A) 2-nucleated embryo sac — second. The nucleus of the functional megaspore divides by mitosis, and the two nuclei move to opposite poles.

(D) 4-nucleated embryo sac — third. Another mitotic division gives four nuclei. These divisions are free nuclear: no cell walls form.

(C) Female gametophyte — fourth. After the 8-nucleate stage, cell walls form. The mature 7-celled, 8-nucleate embryo sac is the female gametophyte.

NCERT Extract:
The Pistil, Megasporangium (ovule) and Embryo Sac – “… Let us study about the formation of the embryo sac in detail. (Figure 1.8b). The nucleus of the functional megaspore divides mitotically to form two nuclei which move to the opposite poles, forming the 2-nucleate embryo sac. Two more sequential mitotic nuclear divisions result in the formation of the 4-nucleate and later the 8-nucleate stages of the embryo sac.”

Figure 1.8 (a) Parts of the ovule showing a large megaspore mother cell, a dyad and a tetrad of megaspores; (b) 2, 4, and 8-nucleate stages of embryo sac and a mature embryo sac; (c) A diagrammatic representation of the mature embryo sac