In human development, an embryo is most sensitive to chemicals, radiation, and pathogens during the first trimester because this is the time when
A) tissues are differentiating.
B) organs are increasing in size.
C) the fetus grows rapidly.
D) fetal movements begin.
E) implantation occurs.

Question

Quizplus · Accepted Answer

During the first trimester, the embryo is undergoing rapid cell differentiation as tissues and organs begin to form. Exposure to harmful substances or pathogens during this critical developmental phase can lead to structural abnormalities or functional deficits.

In Human Development, an Embryo Is Most Sensitive to Chemicals