Teratogens: select one: a. are environmental agents that can harm the embryo or fetus. b. are most damaging during the fetal period of development. c. are only those substances the mother's body produces. d. harm the fetus only when taken in extremely large doses.

The answer is A. Teratogens are substances that impair the proper development of embryo or fetus. They include drugs, infections, radiation, and chemicals. The agents could cause the fetus to be physically or mentally impaired. Children born having been exposed to teratogens that affect their brain development could exhibit reduced IQ, communication challenges, and etcetera.

brain development. a child's brain undergoes an amazing period of development from birth to three—producing more than a million neural connections each second. the development of the brain is influenced by many factors, including a child's relationships, experiences and environment.

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