Which process describes the longer time awake, the drive for sleep need building up and dissipating over sleep?

• A. Process C
• B. Process S
• C. Circadian Rhythm
• D. Homeostatic Process

Answer: (B)

The sleep drive described is the homeostatic sleep pressure, known as Process S. It increases the longer you are awake, building up a need for sleep, and it dissipates during sleep as you recover. This means extended wakefulness raises the urge to sleep, while sleeping lowers that urge back toward baseline. The circadian rhythm, or Process C, governs when you’re naturally more or less alert across the day, shaping timing rather than the amount of sleep pressure from prior wake time. Because the scenario focuses on how sleep need accumulates with time awake and then fades with sleep, it points to the homeostatic sleep drive.