Which of the following statements is true of the impact of teratogens?
A) Very few fetuses are exposed to teratogens, so it is easy to determine which teratogen causes which defect.
B) Fetuses are safe from the effects of teratogens during the first trimester.
C) Teratogens cause anatomical defects only after organogenesis is complete.
D) Exposure to teratogens does more damage when it occurs at some points in development than at others.

Question

Quizplus · Accepted Answer

Exposure to teratogens does more damage when it occurs at some points in development than at others. This is because different organ systems develop at different times during gestation, and each has a sensitive period during which it is particularly vulnerable to teratogenic insult. For example, exposure to alcohol during the first trimester can cause facial abnormalities, while exposure during the third trimester can lead to growth retardation.

Which of the Following Statements Is True of the Impact