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.

After fertilization in an embryo sac, certain cells degenerate to support the development of the embryo and the endosperm. Here’s a detailed explanation of what happens to the cells within the embryo sac:

1. Synergids: These cells are located near the egg cell and play a role in guiding the pollen tube to the egg for fertilization. Once fertilization occurs, the synergids have fulfilled their function and degenerate.
2. Antipodal cells: These cells are situated at the opposite end of the embryo sac from the egg apparatus. Their exact function is less well understood, but they are not involved in the direct process of fertilization. After fertilization, antipodal cells degenerate.
3. Egg cell: The egg cell is fertilized by one of the sperm cells from the pollen tube, forming the zygote, which will develop into the embryo. The egg cell itself does not degenerate; instead, it transforms into the zygote.
4. Central cell: The central cell, which contains two polar nuclei, is fertilized by the other sperm cell from the pollen tube, forming the primary endosperm nucleus. This leads to the development of the endosperm, a tissue that nourishes the developing embryo. The primary endosperm cell does not degenerate; it divides and develops into the endosperm.

Conclusion: After fertilization, the synergids and antipodal cells degenerate, while the egg cell becomes the zygote, and the primary endosperm cell starts forming the endosperm. This explains why the correct answer is: (3) Synergids and antipodal cells degenerate after fertilization.