What is the mechanism used by the kidneys to remove waste products from the body?

Nephrons convert nitrogenous waste to uric acid and pass it out as urine

Nephrons actively transport uric acid and other nitrogenous waste into the proximal and distal convoluted tubules, from where it is collected to form urine.

The blood is filtered to retain cells and large plasma proteins within the blood. The remaining filtrate passes through the proximal and distal convoluted tubules, where needed substances are reabsorbed by active transport

Nephrons filter out the nitrogenous waste which is passed through the proximal and distal convoluted tubules and collected by the collecting duct as urine.