You are watching sleep researchers monitor the sleep of a normal adult. The participant is hooked up to an EEG. What brain waves would you observe as the person becomes drowsy and then enters the first stage of sleep?

alpha brainwaves are eventually replaced by theta

Explanation:

The various stages of sleep are categorized by the trends of each level of the brainwaves. The waves of the alpha are substituted by theta waves as an individual moves from waking to sleeping. In level 2 sleep arise sleep spindles and K-complexes.