The metanephros is the final stage of kidney development in mammals, including humans. It forms during the embryonic period and is responsible for producing urine and filtering blood. The metanephros develops from the mesonephric duct and the surrounding mesenchyme, ultimately becoming the functional kidney. In adults, the metanephros is known as the kidney. It plays a crucial role in maintaining fluid balance, regulating electrolytes, and excreting waste products. The metanephros is essential for proper bodily function and is vital for survival.