Whether you are awake or asleep right now depends on
A) the number of hours since one's last intake of food.
B) sleep-promoting substances in the blood stream.
C) external markers for sleep and wakefulness.
D) the balance between separate sleep and waking systems.

Question

Quizplus · Accepted Answer

The balance between separate sleep and waking systems determines whether you are awake or asleep, as these systems regulate the sleep-wake cycle through various physiological processes.

Whether You Are Awake or Asleep Right Now Depends on