Coral reefs are natural breeding grounds for underwater life, but the Great Barrier Reef is unique because it's the biggest structure made of living organisms on Earth.
(Coral reefs; are; natural breeding grounds for underwater life) (the Great Barrier Reef; is; unique; because it's the biggest structure) (it; 's; the biggest structure made of living organisms on Earth) (the biggest structure; made; of living organisms on Earth)
Coral reefs the Great Barrier Reef it the biggest structure
are is 's made
natural breeding grounds for underwater life
unique because it's the biggest structure
the biggest structure made of living organisms on Earth
of living organisms on Earth