Final answer:
Urine is transported from the kidneys to the bladder via the ureters and is then excreted out of the body through the urethra. The correct sequence is ureter followed by urethra.
Step-by-step explanation:
Once produced, urine travels through the ureters until it reaches the bladder, from which it is released into the external environment through the urethra. Therefore, the correct answer is 1) ureter : urethra. After being formed in the kidneys, urine is collected in the renal pelvis, which is continuous with the ureter. These muscular tubes, one connected to each kidney, are responsible for moving the urine toward the urinary bladder by a process of rhythmic contractions known as peristalsis. The bladder is a hollow, distensible organ responsible for storing urine until it reaches sufficient volume to trigger urination. At that time, a nerve impulse will cause the bladder's sphincter to relax, allowing urine to flow into the urethra. This tube then carries the urine from the bladder to be excreted outside of the body through the external urethral opening, completing the process of urine excretion.