What is characterized by excessive sleepiness, often a symptom of fatigue?

The choice of drowsiness as the correct answer is valid because it directly refers to a state of being sleepy or in a condition of reduced alertness, which aligns with excessive sleepiness often linked to fatigue. Drowsiness can manifest as a tendency to fall asleep in situations that would typically require attention, making it a prominent characteristic associated with fatigue.

In contrast, the other options present different concepts. Naps refer to short periods of sleep, usually taken during the day, and while they can be related to overall sleep patterns, they do not directly characterize a symptom. Somnolence, while it also describes a state of sleepiness, is often used in a more clinical or medical context rather than as a general term. Fatigue, on the other hand, describes an overall state of tiredness and lack of energy, which can lead to drowsiness, but does not itself denote excessive sleepiness directly. By focusing on drowsiness, the answer connects closely with the symptom being described.