Which combining form indicates the color white?

The combining form that indicates the color white is "leuk/o." This term derives from the Greek word "leukos," which means white. In medical terminology, "leuk/o" is commonly used in words related to white blood cells, such as "leukocyte." White blood cells play a crucial role in the immune system, assisting the body in fighting infections and diseases.

The other options focus on different anatomical terms or colors. "Mamm/o" refers to the breast, "hepat/o" pertains to the liver, and "nat/o" means related to birth or born. None of these terms relate to the color white, which reinforces that "leuk/o" is the correct choice as it specifically denotes whiteness in medical contexts.