Which of the following cells degenerate after fertilization in an embryo sac?

Synergids and antipodal cells degenerate after fertilization.

The correct answer is Option (3) - Synergids and antipodal cells degenerate after fertilization.

Explanation: The embryo sac, also known as the female gametophyte, is located within the ovule of a flowering plant. It is formed from the megaspore through a process called megagametogenesis.

During fertilization, one of the two sperm cells in the pollen tube fuses with the egg cell (located at the micropylar end of the embryo sac) to form the zygote, which develops into the embryo. The other sperm cell fuses with the secondary nuclei in central cell of the embryo sac, resulting in the formation of the primary endosperm cell.

After fertilization, the synergids, which are located at the micropylar end of the embryo sac and help guide the pollen tube to the egg cell, degenerate and are no longer functional. Similarly, the antipodals, which are located at the chalazal end of the embryo sac and have an unclear function, also degenerate.

The primary endosperm cell, on the other hand, does not degenerate after fertilization. Instead, it undergoes multiple rounds of cell division to form the endosperm, which provides nourishment to the developing embryo.

Therefore, the correct statement is: (3) Synergids and antipodals.