A nurse manager is conducting an in-service about the physiological functions of sleep for a group of staff nurses. Which of the following statements by one of the nurses indicates an understanding of the teaching?

"Sleep is a process that decreases the development of new neural pathways that assist with retention of knowledge and memorization."

"The brain and neurons continue to communicate with each other during sleep to remove toxins that built up in the brain while awake."

"The circadian rhythm is an external process that controls the sleep-wake cycle."

"Clients experience the highest quality sleep when they complete three out of the four stages of sleep."