Question

The effects of teratogens select one:

a. are predictable and straightforward.
b. are usually the most serious during the fetal period.
c. vary with the age of the organism at the time of exposure.
d. are always detectible at birth.

Answer 1

The effects of teratogens vary with the exposure time and are not predictable; they can lead to birth defects depending on the timing and amount of exposure.

Step-by-step explanation:

The effects of teratogens vary with the age of the organism at the time of exposure. This variation is because each organ of the fetus develops during specific periods in the pregnancy, known as the critical or sensitive period. The time during which a developing fetus is exposed to a teratogen can significantly affect the development and potential birth defects. The severity of these defects can be influenced by the duration and dose of teratogen exposure, the degree of transfer from maternal to fetal circulation, and the susceptibility of the fetus to teratogenesis. For instance, alcohol use during pregnancy can lead to fetal alcohol spectrum disorders, which can cause a variety of physical and cognitive impairments that persist into adulthood, depending on the timing and amount of alcohol consumed.

Answer 2

The right answer is C) Vary with the age of the organism at the time of exposure.

Conventionally, teratogenic drugs have been defined as drugs that can induce visible malformations in newborns, which may interfere with the placement of embryonic organs. These effects are mainly related to exposures in early pregnancy (the period during which the risk is greatest corresponds to the first trimester of pregnancy).