What term describes the metabolic wastes expelled by the kidneys?

The term that describes the metabolic wastes expelled by the kidneys is urine. The kidneys play a crucial role in the excretory system by filtering blood, removing waste products, and regulating various body functions, including fluid balance and electrolyte levels. During this filtration process, the kidneys convert the waste and excess substances into urine, which is collected in the bladder before being expelled from the body.

Urine contains urea, creatinine, various ions, and other metabolic byproducts. While urea is indeed a major component of urine, it specifically refers to one type of waste product formed from the breakdown of proteins. Filtrate refers to the fluid that has been filtered by the kidneys but has not yet been processed into urine, and stool pertains to the wastes expelled from the digestive system, which is different from renal excretion. Thus, the best term to describe the end product of kidney excretion is urine.