A teratogen is best defined as which?

A teratogen is best defined as which?

• A. A substance that damages a developing fetus
• B. A mutated gene in an embryo
• C. A substance that causes cancer
• D. An animal that developed abnormally in utero

Answer: (A)

Teratogens are agents that can interfere with fetal development and cause birth defects or other developmental problems. A substance that damages a developing fetus best captures this idea, since the teratogenic effect is about harm to the developing fetus itself. The other choices describe a genetic mutation, a cancer-causing substance, or an abnormal fetus as the agent or outcome, which are not what teratogens refer to. In real-world terms, teratogens include certain drugs, chemicals, infections, or radiation, and their impact depends on timing and dose during development.

Teratogens are agents that can interfere with fetal development and cause birth defects or other developmental problems. A substance that damages a developing fetus best captures this idea, since the teratogenic effect is about harm to the developing fetus itself. The other choices describe a genetic mutation, a cancer-causing substance, or an abnormal fetus as the agent or outcome, which are not what teratogens refer to. In real-world terms, teratogens include certain drugs, chemicals, infections, or radiation, and their impact depends on timing and dose during development.