During low intensity cardiovascular exercise the fuel that contributes the highest percentage to atp production is:

During low intensity cardiovascular exercise the fuel that contributes the highest percentage to ATP is Fat.

Fat is the body's preferred source of energy for the low intensity exercise. While at rest and during low intensity exercise, free fatty acids are the predominant energy sources. The process by which fatty acids and other sources are converted to energy during low intensity is described as aerobic (meaning that it occurs in presence of oxygen).