Why do harmful agents cause the most severe birth defects during the embryonic period?
A) This is a period of rapid differentiation when cells and tissues acquire specific functions and organs form.
B) This is the period when substances pass most easily through the placenta.
C) The mother's hormones are at the highest levels at this time.
D) The embryo has not yet implanted into the uterus.

Question

Quizplus · Accepted Answer

During the embryonic period, which lasts from fertilization to the end of the eighth week of gestation, the basic structure and function of all major organs and systems are established. Harmful agents can cause severe birth defects because they can disrupt the intricate and tightly controlled processes of cell differentiation and organ formation that occur during this period.

Why Do Harmful Agents Cause the Most Severe Birth Defects