The term "abyssal" refers to the deep-sea environment found at depths of 3,000 to 6,000 meters (about 9,800 to 19,700 feet) below the ocean's surface. This zone is characterized by extreme pressure, low temperatures, and complete darkness. The abyssal zone is home to unique ecosystems and organisms, such as abyssal fish and deep-sea invertebrates, which have adapted to survive in these harsh conditions. Abyssal plains, which are flat areas of the ocean floor, make up a significant portion of the Earth's surface. These plains are formed by the accumulation of sediments over time and are often found between the continental rise and mid-ocean ridges. The study of the abyssal zone is important for understanding marine biodiversity and the impact of human activities, such as deep-sea mining and ocean pollution.