Final answer:
By the end of Randy Gardner's experiment on sleep deprivation, he experienced enhanced sensory perception and hallucinations.
Step-by-step explanation:
Randy Gardner's experiment is related to sleep deprivation, which is a topic in Biology. By the end of his experiment, Randy Gardner experienced the effects of sleep deprivation, which included enhanced sensory perception and hallucinations. His physical senses became extremely keen and alert, allowing him to notice details he wouldn't normally perceive. For example, he could see individual trees, leaves, and insects in the forest, and he heard the separate sounds of ripples and the movements of different creatures.