Final answer:
Sleep is composed of different stages characterized by specific brain wave activity. Deep sleep or slow-wave sleep, which is associated with low frequency and high amplitude waves, is characterized by delta waves.
Step-by-step explanation:
Sleep is composed of several different stages that can be differentiated by the patterns of brain wave activity. The specific brain waves associated with deep sleep or slow-wave sleep, which is characterized by low frequency and high amplitude waves, are called delta waves. These delta waves have the lowest frequency and highest amplitude of our sleeping brain wave patterns.