Deep-sea features include various underwater formations found in the ocean's depths. These features consist of trenches, mountains, ridges, and plains. The Mariana Trench, the deepest part of the world's oceans, is a notable example of a trench, while the Mid-Atlantic Ridge is a significant underwater mountain range formed by tectonic activity. Another important deep-sea feature is the abyssal plain, which covers large areas of the ocean floor and is characterized by flat, sediment-covered regions. Additionally, seamounts are underwater volcanoes that rise from the ocean floor, often creating unique ecosystems that support diverse marine life.