What is the name of the largest living thing on earth, which is actually a massive ecosystem of islands and coral reefs?

The Great Barrier Reef was considered the largest living thing and was actually composed of the skeletons of coral, which combined to be so large that they were the size of islands. The reef supported its own ecosystem. 

They use the si unit, or metric system its all the same thing

Hiya,  (the properties of carbon depends on the structure of said element.)  although, carbon is not cohesive or adhesive.carbohydrates contain carbon, hydrogen, and oxygen.  it can bond with other carbon atoms as well as other elements.a polymer is a big ole' molecule made from smaller molecules that decided to smack together and form a covalent bond. but it is fact that carbon often forms polymers.decomposition of molecules simply means the organism is clearly dead and the molecules of said dead organism can be reutilized by living organisms.hope this !