What is the primary function of the kidneys?

The primary function of the kidneys is indeed to excrete urine and waste products. This critical role helps maintain the body's fluid and electrolyte balance while removing toxins and metabolic waste from the bloodstream. The kidneys filter blood, a process that leads to the formation of urine, which consists of water, urea, electrolytes, and other waste materials.

Through this process, the kidneys play an essential part in regulating various physiological functions. By excreting waste, they not only rid the body of harmful substances but also help in maintaining the homeostasis of bodily fluids. The urine produced is a direct outcome of the kidneys’ filtration activity, showcasing their pivotal role in waste elimination.