In an embryo sac, the cells that degenerate after fertilisation are:
a. Synergids and primary endosperm cell
b. Synergids and antipodals
c. Antipodals and primary endosperm cell
d. Egg and antipodals.
The answer is the option (b) Synergids and antipodals
PEN provides food for the growing embryo, while egg develops into the embryo. Hence, option (b) is the correct answer.