Which of the following pharmacokinetic change(s) occur(s) with aging?
1. Absorption is altered by a decrease in the gastric pH.
2. Metabolism is decreased by a reduced liver mass.
3. Distribution is altered by a decrease in total body fat.
4. Excretion is reduced because of lessened renal blood flow.

(1) and (3)

(2) and (4)

(1) (2) (3)

All of the above

(4) only