Answer: Australia
Notes: Recently, the Great Barrier Reef recorded its steepest decline in hard coral cover in nearly 40 years due to climate change-induced heat stress, cyclones, and coral-eating starfish outbreaks. It is located in the Coral Sea, off northeastern Australia. It is the world’s longest and largest reef complex and the largest living structure on Earth. It stretches over 2,000 km, covering around 350,000 sq. km, and forms about 10% of global coral reef ecosystems. It consists of about 2,100 individual reefs and 800 fringing reefs, with 400 coral types, 1,500 fish species, and 4,000 mollusk species.
