Yes, the Great Barrier Reef is a major international tourist attraction, receiving more than 2 million visitors per year.  The reef is also an important destination for many recreational and commercial activities, including fishing, diving, snorkeling, sailing, and whale watching.
assistant
Yes, the Great Barrier Reef is a major international tourist attraction, receiving more than 2 million visitors per year.  The reef is also an important destination for many recreational and commercial activities, including fishing, diving, snorkeling, sailing, and whale watching.  Unfortunately, coral reefs are very sensitive to environmental changes, and are now suffering widespread destruction due to ocean acidification, pollution, and increased ocean temperatures.
assistant
What is coral? Like is it alive?
user
Yes, coral is actually a type of animal.  Coral is an aggregate organism consisting of millions of tiny soft-bodied polyps.  These polyps secrete a hard skeleton of calcium carbonate which then forms the coral reef.  Coral is an important component of many marine ecosystems, providing shelter and habitat for a wide variety of other animals, as well as serving as a food source for many species.  Coral reefs are unfortunately very sensitive to environmental changes, and are now suffering widespread destruction due to ocean acidification, pollution, and increased ocean temperatures.
assistant
what's the biggest coral reef in the world?
user
The largest continuously-growing coral reef is the Great Barrier Reef of Australia, which runs for over 2,000 miles (approximately 3,219 km) along the northeast coast of Australia.  The reef is home to an extraordinarily rich diversity of marine life, and is a major tourist attraction.  Unfortunately, the Great Barrier Reef is now suffering from significant degradation due to ocean acidification, pollution, and increased ocean temperatures.
assistant
Are coral reefs quite biodiverse?
user
Yes, coral reefs have the highest biodiversity of all marine ecosystems.  Over 1500 species of hard corals have been identified on the Great Barrier Reef alone, along with over 4000 species of fish, and over 2000 species of mollusks.  Coral reefs also provide habitat for many other types of organisms, including sponges, sea squirts, barnacles, turbellarians, echinoderms, crustaceans, bryozoans, worms, sea stars, sea pens, sea anemones, jellyfish, sea cucumbers, and tunicates.  Unfortunately, coral reefs are now suffering widespread destruction due to ocean acidification, pollution, and increased ocean temperatures.
assistant
Is the Great Barrier Reef used for tourism>
user