Final answer:
Approximately 80% of all gallstones are composed of a mixture of cholesterol, bilirubin, and calcium salts.
Step-by-step explanation:
True. Approximately 80% of all gallstones are composed of a mixture of cholesterol, bilirubin, and calcium salts. When a large amount of cholesterol accumulates in the gallbladder, it turns into solid particles known as gallstones. These gallstones are mostly cholesterol with a small amount of calcium salts, bilirubin, glycerophospholipids, and fatty acids.