What is the primary function of the urinary system?

The primary function of the urinary system is to remove waste from the blood and produce urine. This system plays a critical role in maintaining the body's internal balance by filtering out toxins and excess substances that could be harmful if allowed to accumulate. The kidneys, a vital component of the urinary system, filter blood to remove waste products, which can include urea, creatinine, and other metabolites. The filtered waste is then expelled from the body in the form of urine, which is stored in the bladder until it is eliminated through the urethra.

The other choices represent functions of different body systems. The production of digestive enzymes is associated with the digestive system, which breaks down food; nutrient absorption is also a key function of the digestive system. Transporting food to the stomach is a mechanical process primarily involved with the anatomy of the digestive tract. Thus, the urinary system's unique role of waste removal distinctly highlights its primary function.