Reefs are underwater structures made of coral and other materials, providing a home for many marine creatures. They are often found in warm, shallow waters and are known for their vibrant colors and diverse ecosystems. Coral reefs, in particular, are formed by tiny animals called coral polyps that build hard skeletons, creating a habitat for fish, sea turtles, and other sea life. These ecosystems are crucial for the health of our oceans, as they protect coastlines from erosion and support fishing industries. However, reefs face threats from climate change, pollution, and overfishing, making their conservation essential for maintaining marine biodiversity.