What is the role of the gall bladder in digestion?

The gall bladder plays a crucial role in digestion by storing bile that is produced by the liver. Bile is a digestive fluid that helps in emulsifying fats, making it easier for enzymes to break down the fat molecules during digestion. When food, particularly fatty food, enters the small intestine, the gall bladder releases the stored bile into the intestine to aid in the digestion and absorption of these fats. This function is essential for effective digestion and nutrient absorption, specifically for lipids.

The other options describe functions of different organs or systems. For example, absorbing nutrients from digested food is primarily the function of the small intestine, not the gall bladder. Regulating blood pH levels is a role of the kidneys and the respiratory system, while filtering waste from urine is a function of the kidneys as well. Thus, the primary role of the gall bladder is accurately captured by its function in bile storage.