What is the largest organism in yhe world and where does it live

Armillaria

Explanation:

In fact, the blue whale is not the biggest organism in the world, though it is the biggest animal in the world, the Humongous Fungus is the largest organism in the world. It stretches over 2,385 acres of Malheur National Forest, Oregon. It's our largest organism, and from the way the fungus has been growing, it may also be our oldest organism.

The world's largest living thing is even bigger than a blue whale (which happens to be the largest animal living now). Meet Armillaria ostoyae, or, as it's nicknamed, the Humongous Fungus. It's an organism that covers 2,385 acres (almost 4 square miles) of the Malheur National Forest in Oregon.