The Behavioral and Long-Term Consequences of Prenatal Exposure to Smoke

The behavioral and long-term consequences of prenatal exposure to smoke are not very well understood because

A) prenatal exposure to smoke is often confounded with postnatal exposure to smoke.
B) prenatal exposure to smoke has the same teratogenic effects as aspirin.
C) the placenta is not directly affected by cigarette smoke.
D) babies who were exposed to smoke prenatally are not physically different at birth.