The correct answer to this question is Urinary Bladder. This organ is also just known as the bladder. It resembles a bag and is round in shape. The urinary bladder gets its name from the function of storing urine. The pelvic area houses the urinary bladder, and it is behind the pelvic bone. It is also right under the kidneys.
The urinary bladder is seen as a storage tank because it holds the urine. Despite this description, the urinary bladder is much more complex in design. Its size resembles that of a grapefruit. Along with the large size, the bladder can stretch and shrink.