Coral reefs are large underwater structures composed of calcium carbonate secreted by corals. These reefs are formed when coral polyps secrete a hard exoskeleton around themselves for protection. Over time, the skeletons accumulate and form the base structure of the reef. Coral reefs are typically found in warm, shallow waters with plenty of sunlight to support photosynthesis in the symbiotic algae that live within the corals. These algae provide the corals with energy, while the corals provide the algae with nutrients. This mutually beneficial relationship is crucial for the survival of coral reefs. As the coral polyps continue to grow and reproduce, the reef expands both vertically and horizontally. The growth rate of coral reefs varies depending on factors such as water temperature, nutrient availability, and wave action. Some reefs can grow up to 10 cm per year, while others grow much more slowly. In addition to providing a habitat for a diverse range of marine life, coral reefs also act as natural barriers that protect coastlines from erosion and storm damage. Unfortunately, coral reefs are increasingly threatened by human activities such as overfishing, pollution, and climate change. It is essential to protect and preserve these valuable ecosystems for future generations.