A narrow body of water that connects two larger bodies of water is called a strait. Straits can vary significantly in size, depth, and geographical feature, often serving as vital maritime passages for ships and marine life. The formation of straits can occur due to tectonic activity, erosion, or the rising and falling of sea levels. Notable examples include the Strait of Gibraltar, which connects the Atlantic Ocean to the Mediterranean Sea, and the Bering Strait, linking the Arctic Ocean with the Bering Sea. They are crucial for navigation, trade, and ecological diversity, playing a key role in the mixing of marine environments.