Final answer:
Sleep serves three main functions: restoration, preservation and protection, and consolidation.
Step-by-step explanation:
Sleep serves several main functions: restoration, preservation and protection, and consolidation. First, sleep allows the body and brain to restore and recover from the physical and mental demands of daily activities. Second, sleep helps to preserve and protect the body by promoting immune function and repairing damaged cells and tissues. Finally, sleep is important for consolidation of memories and learning, as it helps to strengthen the connections between neurons and solidify new information.