Given a scientific passage and an answer, generate a question for the given answer.
Q: Passage: Aldosterone Recall that aldosterone increases the excretion of potassium and the reabsorption of sodium in the distal tubule. Aldosterone is released if blood levels of potassium increase, if blood levels of sodium severely decrease, or if blood pressure decreases. Its net effect is to conserve and increase water levels in the plasma by reducing the excretion of sodium, and thus water, from the kidneys. In a negative feedback loop, increased osmolality of the ECF (which follows aldosterone-stimulated sodium absorption) inhibits the release of the hormone (Figure 26.13). Answer: sodium
A: 
The net effect of aldosterone is to conserve and increase water levels in the plasma by reducing the excretion of what element, and thus water?