Final answer:
The answer is D. all of the above, indicating that in the U.S., there are prohibitions against marriage between close blood relatives and affinal relatives.
Step-by-step explanation:
According to the text's discussion of the incest taboo, the correct answer is D. all of the above. This means that in the United States:
- The majority of states prohibit marriage between half-siblings and first cousins.
- Some states have laws against marriage between second cousins, and even more distant relatives.
- Some states also prohibit marriage between affinal relatives, those related by marriage rather than by blood.
This taboo is a norm present in all societies, though the specifics of prohibited relations can vary. Incest avoidance serves as a mechanism to prevent close relatives from entering into sexual relationships, thereby promoting genetic diversity.