Coral reefs are formed by millions of polyps. Which term matches this description?

• A. Coral reefs
• B. Seamounts
• C. Kelp forests
• D. Mangrove swamps

Answer: (A)

Polyps are tiny marine animals that live in colonies and secrete calcium carbonate skeletons. When millions of these polyps build up, their skeletons form reef structures, known as coral reefs. So the term that matches this description is coral reefs. Seamounts are underwater mountains from volcanic activity, kelp forests are large areas of seaweed, and mangrove swamps are coastal wetlands—none are formed by polyps in the same way coral reefs are.