The Great Barrier Reef is a :
Answer: (2) Coral Formation
The great barrier reef is a Coral formation. It is the largest coral reef system in the world. It is found in the coral sea. It is also the largest living structure of the world. It consists 2900 individual reefs and 900 islands.
It is located in the Coral sea of the coast of Queensland, Australia. The length of this reef is 2600 km.