What is the main role of the gallbladder?

The gallbladder's primary function is to store and concentrate bile that is produced by the liver. Bile is a digestive fluid that plays a crucial role in the digestion and absorption of fats in the small intestine. When food, especially fatty food, enters the small intestine, the gallbladder releases the stored bile into the digestive tract to aid in the emulsification of fats, making them easier to digest. This process is essential for effective digestion, allowing nutrients to be absorbed more readily.

The other options pertain to different organs and functions within the body. For example, insulin production is the role of the pancreas, filtering toxins from the blood is primarily the function of the liver and kidneys, and the production of digestive enzymes occurs in the pancreas and the salivary glands. Thus, the gallbladder is specifically specialized for the storage and concentration of bile, making it integral to the digestive process.