ANATOMY

Detailed explanation-1: -The kidneys filter unwanted substances from the blood and produce urine to excrete them. There are three main steps of urine formation: glomerular filtration, reabsorption, and secretion. These processes ensure that only waste and excess water are removed from the body.

Detailed explanation-2: -The counter-current mechanism is not a part of urine formation, it is a process that makes the urine more concentrated.

Detailed explanation-3: -Answer and Explanation: The physiological function that is not a function of the urinary system is C. Gas exchange.

Detailed explanation-4: -Filtration. Reabsorption. Regulated reabsorption, in which hormones control the rate of transport of sodium and water depending on systemic conditions, takes place in the distal tubule and collecting duct. Secretion. Excretion.