Final answer:
The kidney removes nitrogen and protein waste products, primarily in the form of urea, from digestion.
Step-by-step explanation:
The kidney removes multiple waste products from digestion, including nitrogen and protein. Nitrogenous waste is produced during the breakdown of proteins and is excreted in the form of urea. Urea is a by-product of protein catabolism and is one of the main waste products removed by the kidneys.