What is the name for the largest form of sculpture—usually additive, but sometimes subtractive—which uses the surface of the globe, or the natural environment, as its primary material?

The name for the largest form of sculpture is GREAT SERPENT MOUND

Explanation:

The Great Serpent Mound is considered as the largest sculpture in the world. It is located in the rural areas of southwest Ohio. The Great Serpent Mound has a length of approximately 1300 feet, a height which varies from about 1 to 3 feet and a width of 20 to 25 feet. It is slightly crescent shaped with such an orientation that its head. It is thought to be made by previously settled people of the area who used to cultivate maize, beans and squash.