Answer:
Beta waves
Explanation:
As Isaac reads his textbook, he gets more and more drowsy and is just about to fall asleep. His brain activity will most likely be characterized by beta waves.
Beta waves are the characteristic brain waves during our active state of consciousness and they are replaced by alpha waves when we fall asleep. Since Isaac is still awake and not yet fully asleep, his brain waves are better waves which will be replaced by alpha waves when he finally falls asleep.
