Final answer:
The man's olfactory nerve was destroyed, affecting his sense of smell.
Step-by-step explanation:
If a man can no longer enjoy food through his sense of smell after hitting his head on a windshield, it means that he has lost his sense of smell or olfaction. The cranial nerve responsible for the sense of smell is the Olfactory nerve. Damage to this nerve can occur as a result of head trauma, such as in a car accident.
Learn more about Olfactory nerve and sense of smell