The fluid leaving the collecting ducts at the is called urine.

The fluid that leaves the collecting ducts at the end of the urinary system is indeed called urine. Here's a step-by-step explanation:

1. The process begins in the kidneys, where blood is filtered to remove waste products and produce a fluid called filtrate.

2. This filtrate then travels down the renal tubules in the kidneys. As it does so, necessary substances like glucose, amino acids, and certain ions are reabsorbed back into the blood.

3. The remaining fluid, now concentrated with waste products, continues its journey into the collecting ducts. These ducts serve as the final location for the reabsorption of water and certain ions, further concentrating the fluid.

4. Finally, the concentrated fluid, now called urine, leaves the collecting ducts and travels down the ureters to the bladder, where it is stored until it can be excreted from the body through the urethra.