Final answer:
A teratogen is any environmental agent that causes damage to the developing embryo or fetus. Alcohol, cigarette smoke, prescription drugs, and nutrient deficiencies are examples of teratogens that can cause physical defects and developmental problems in the unborn fetus.
Step-by-step explanation:
A teratogen is any environmental agent-biological, chemical, or physical-that causes damage to the developing embryo or fetus. Examples of teratogens include alcohol, cigarette smoke, various prescription drugs, and nutrient deficiencies.
These substances can cause physical defects and developmental problems in the unborn fetus. The effects of teratogens can range from minor to major, with long-lasting consequences for the child.