What does urine primarily consist of?

Urine primarily consists of water and electrolytes, making it essential for maintaining the body's fluid balance and homeostasis. Water makes up about 95% of urine, serving as a solvent for various waste products and solutes. Electrolytes, including sodium, potassium, calcium, and chloride, are crucial for numerous physiological processes, including nerve function, muscle contraction, and hydration. The composition of urine reflects the balance the kidneys maintain in filtering and excreting waste products and excess substances from the bloodstream. This helps regulate overall bodily functions and maintain a stable internal environment. The other options involve components that do not accurately reflect the primary constituents of urine.