Q. The longest period of prenatal development is the

Explanation by: Mr. Dubey

The third and longest period of prenatal development, extending from the ninth week until birth is Fetal period.

The process of prenatal development occurs in three main stages. The first two weeks after conception are known as the germinal stage, the third through the eighth week are known as the embryonic period, and the time from the ninth week until birth is known as the fetal period.