Deep-sea zones refer to the different layers of the ocean that vary in depth, light, and temperature. The ocean is divided into several zones, including the epipelagic zone (sunlit surface), the mesopelagic zone (twilight), and the bathypelagic zone (dark). Each zone hosts unique ecosystems and marine life adapted to specific conditions. The deepest part of the ocean is the abyssopelagic zone, which extends from about 13,000 feet to 20,000 feet below the surface. This zone is characterized by extreme pressure, cold temperatures, and complete darkness. Organisms found here, such as anglerfish and giant squid, have special adaptations to survive in such harsh environments.