Coral reefs are formed through the accumulation of calcium carbonate secreted by coral polyps, which thrive in shallow, warm waters on continental shelves.

Volcanic islands are formed when magma from a volcanic eruption cools and solidifies above sea level.

An atoll is a ring-shaped coral reef that encircles a lagoon and is typically found in the central or western Pacific Ocean.

Platform reef is not a major type of coral reef. The three main types of coral reefs are fringing reefs, barrier reefs, and patch reefs.

Accretion is the process by which coral reefs grow vertically through the accumulation of calcium carbonate secreted by coral polyps.

Volcanic eruptions are not a major threat to coral reefs. The primary threats to coral reefs include climate change, overfishing, pollution, and coastal development.

The relationship between coral and zooxanthellae is mutualistic, meaning both organisms benefit from the association.

Mangroves are not a major group of organisms found in coral reef ecosystems. The major groups of organisms found in coral reef ecosystems include fish, coral, sea turtles, and invertebrates.

Coral degradation is the process by which coral reefs are damaged or destroyed due to various factors such as climate change, pollution, and overfishing.

Introducing invasive species is not a major conservation strategy for protecting coral reefs. The major conservation strategies for protecting coral reefs include establishing marine protected areas, reducing pollution, and promoting sustainable fishing practices.

Coral restoration is the process by which coral reefs recover from damage or destruction through active human intervention.

Mineral extraction is not a major economic benefit of coral reefs. The major economic benefits of coral reefs include tourism, fisheries, and coastal protection.

Coral propagation is the process by which coral reefs are artificially propagated and grown through human intervention.

Lack of public awareness is not a major challenge in conserving coral reefs. The major challenges in conserving coral reefs include climate change, pollution, and overfishing.

Coral bleaching is the process by which coral reefs become bleached and lose their color due to stress factors such as elevated water temperatures.