Final answer:
All the given options, nicotine in cigarette smoke, some vitamins, and alcohol, are examples of teratogens that can negatively impact fetal development.
Step-by-step explanation:
An example of a teratogen is d) All of these. This includes nicotine in cigarette smoke, certain vitamins when taken in excessive amounts, and alcohol. Teratogens are environmental agents that cause damage to the developing embryo or fetus, which may lead to birth defects or developmental issues. Nicotine and alcohol easily cross the placenta affecting fetal development, and high levels of certain vitamins may also be detrimental during pregnancy.
A teratogen is any environmental agent-biological, chemical, or physical-that causes damage to the developing embryo or fetus. Some examples of teratogens include nicotine in cigarette smoke, alcohol, and certain drugs. Nicotine in cigarette smoke is considered a teratogen because it can cross the placenta and affect the fetus. Alcohol is also a teratogen and can cause fetal alcohol spectrum disorders with life-long consequences.