The answer is urethra.
It is known that the kidneys are responsible for filtration of metabolic wastes from the blood and form urine. Urine is transported through the ureters to the urinary bladder. From the urinary bladder, urine is transported to the outside of the body by the urethra.
The difference in an area with high concentration and an area with low concentration is called concentration gradient.
<h3>What is concentration gradient?</h3>
Concentration gradient refers to the difference between the concentrations of two solutes in a solution.
A solution usually contains an area or region with higher concentration and an area with lower concentration.
The difference between these two areas of different concentrations is referred to as a concentration gradient.
Learn more about concentration gradient at: brainly.com/question/13050811
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