What is the main role of bile in the body?

The main role of bile in the body is to aid in the digestion of fats. Bile, produced by the liver and stored in the gallbladder, contains bile acids that are essential for emulsifying fats in the small intestine. This emulsification process breaks down large fat globules into smaller micelles, increasing the surface area available for digestive enzymes to act upon. Consequently, bile facilitates the absorption of fat-soluble vitamins (A, D, E, and K) and essential fatty acids into the intestinal lining, which play crucial roles in various bodily functions, including energy production and nutrient absorption.

The other options describe functions that, while important, do not directly pertain to the primary role of bile. Filtering toxins is primarily the function of the liver and kidneys, regulating blood flow involves the cardiovascular system, and balancing pH levels is managed through various buffering systems in the body rather than a direct action of bile.