submarine

A submarine is a type of watercraft that can travel underwater and is designed to operate in the ocean. Submarines are used for various purposes, including military defense, research, exploration, and rescue missions. They are built with strong, pressure-resistant materials to withstand deep-sea conditions. Submarines can be manned or unmanned, and they typically have systems for navigation, communication, and life support. Their design allows them to dive and surface, enabling stealthy movement and lengthy underwater missions. Submarines play a crucial role in naval operations and scientific investigations of marine environments.