What is the primary function of the urinary system?

The primary function of the urinary system is to remove waste products from the body and regulate electrolyte balance. This system includes the kidneys, ureters, bladder, and urethra, working together to filter blood, excrete waste materials as urine, and maintain the body's fluid and electrolyte homeostasis.

The kidneys play a crucial role in this process by filtering out toxins, excess salts, and urea from the bloodstream while reabsorbing necessary substances like water and electrolytes back into circulation. This regulation helps maintain blood pressure, volume, and the chemical composition of body fluids, ensuring proper physiological function.

In contrast, other options do not accurately capture the primary role of the urinary system. Producing hormones, while a function of certain organs within the body (like the kidneys producing erythropoietin), is not the main focus of the urinary system. Regulating heart rate is the responsibility of the cardiovascular system. Digesting food is primarily managed by the digestive system. Thus, the comprehensive waste removal and electrolyte regulation role of the urinary system is best highlighted by the correct answer.