Which of the following combinations correctly represents the haploid, diploid, and triploid structures in a fertilized embryo sac?

Synergid, zygote, and primary endosperm nucleus

The correct answer is Option (1) -Synergid, zygote, and primary endosperm nucleus

In a fertilized embryo sac, the correct combination of haploid, diploid, and triploid structures is as follows:

(1) Synergid, zygote, and primary endosperm nucleus: This combination is correct.

• The synergids are two cells that are located at the micropylar end of the embryo sac. They are responsible for attracting the pollen tube and guiding it to the egg cell. Once the pollen tube has entered the embryo sac, the synergids degenerate.These are haploid .
• The zygote is the fertilized egg cell. It is diploid.It divides mitotically to form the embryo.
• The primary endosperm cell divides repeatedly and forms a triploid endosperm tissue. The cells of this tissue are filled with reserve food materials and are used for the nutrition of the developing embryo.

(2) Synergid, antipodal, and polar nuclei: This combination is incorrect. The synergid is haploid, the antipodal cells are haploid, but the polar nuclei are diploid.

(3) Antipodal, synergid, and primary endosperm nucleus: This combination is incorrect. The antipodal cells are haploid, the synergid is haploid, but the primary endosperm nucleus is triploid.

(4) Synergid, polar nuclei, and zygote: This combination is incorrect. The synergid is haploid, the polar nuclei are diploid, and the zygote is diploid.