Final answer:
If glomerular filtration is reduced, urea removal decreases.
Step-by-step explanation:
If glomerular filtration is reduced, urea removal decreases. Glomerular filtration is the process by which waste products, including urea, are filtered from the blood by the glomerulus in the kidney. If filtration is reduced, less urea will be removed from the blood, leading to higher levels of urea in the body.