Urea is transported by blood to the?

Kidneys.

The kidneys are two bean-shaped organs located near the middle of the back. They play a vital role in filtering waste products and excess water from the blood, and regulating the levels of electrolytes in the body. Urea is a waste product that is produced when protein is broken down in the body. It is transported by blood to the kidneys, where it is filtered out and excreted in urine.