What is the main function of the gallbladder?

The main function of the gallbladder is to store and concentrate bile. Bile is a digestive fluid produced by the liver that is essential for the digestion and absorption of fats in the small intestine. Once the liver produces bile, it is transported to the gallbladder, where it is stored until needed. When food, particularly fatty food, enters the small intestine, the gallbladder releases the concentrated bile to help emulsify and break down the fats for better absorption.

This function is crucial for efficient digestion, as it allows the body to manage and utilize bile effectively rather than continuously producing it, which would be inefficient. In contrast, other functions mentioned in the incorrect options do not pertain to the gallbladder. Insulin production is a function of the pancreas, filtering waste primarily occurs in the kidneys, and nutrient absorption is mainly done by the walls of the intestines, not the gallbladder.