4. Which of the following statements about excretory system is NOTTRUE?
(A) Nephron is the functional unit of kidney
(B) The nephron consists of a single long tubule and a ball ofcapillaries called the glomerulus. Filtration occurs as bloodpressure forces fluid from the blood in the glomerulus intothe lumen of Bowman's capsule
(C) Filtration of small molecules s passes through three regions ofthe nephron: the proximal tubule, the loop of Henle, and thedistal tubule, which are all permeable to salt but not towater
(D) The controlled movement of ions (such as

)in the proximal and distal tubules contributes to constantpH in the body fluid