Final answer:
Alcohol is not likely to be transmitted to the fetus through the placenta. However, substances like HIV, narcotics, and certain medications can pass through the placenta and harm the fetus. Correct option is 2.
Step-by-step explanation:
Alcohol is not likely to be transmitted to the fetus through the placenta. Although the placenta is permeable to lipid-soluble substances that can be dangerous or fatal to the developing embryo or fetus, like alcohol, it does not mean that all these substances will definitely pass through the placenta. However, alcohol consumption during pregnancy can still cause fetal alcohol spectrum disorders.
Other substances like HIV, narcotics, and certain medications can pass through the placenta and have the potential to harm the fetus.