During which period of human prenatal development does the congenital defects occur?

 # During which period of human prenatal development does the congenital defects occur?

A. Period of ovum

B. Period of embryo

C. Period of morula

D. Period of fetus

The correct answer is B. Period of embryo.

Congenital defects can occur during the period of embryo development. This period typically spans from the third to the eighth week after fertilization. It is during this time that the major organs and body systems begin to form, making the embryo particularly susceptible to external factors that can interfere with normal development and result in congenital defects.