urethra

The urethra is the tube that carries urine from the bladder out of the body, and it is the last station of the urine path: kidney → ureter → bladder → urethra. It is the one tube in the path that is not paired — the two ureters bring urine down from the two kidneys, and the single urethra empties the bladder — and in males it is also the tube semen leaves the body through, which is why the male reproductive and urinary systems share it. The word a question uses tells the station: a tube from the kidney is a ureter, and a tube out of the body is the urethra. Reading the two names as one is the mistake the exam is built to catch, so answer with the station the question names, not with whichever spelling looks familiar.