As fluid passes down the proximal convoluted tubule, there is a fall of more than 50 per cent in the

A. False Sulphate concentration rises since relatively more water than sulphate is reab-sorbed.

B. False It is little changed, since similar proportions of sodium and water are reabsorbed.

C. True These are completely reabsorbed by active transport.

D. False Potassium is reabsorbed in proportion to water.

E. True Due to reabsorption of about 80 per cent of the water