The passage indicates that the volunteers followed the same diet during each
two-week period of the study. Why was this important?
A. Had the volunteers varied their diets throughout the study, the differences
in urine production may have been attributable to differences in solid food
consumption, rather than in liquid consumption.
B. Had the volunteers varied their diets throughout the study, they may have
craved different amounts of liquid each week.
C. By eating the same foods each week, the volunteers ensured that they did
not suffer from any nutritional imbalances throughout the study.
D. By feeding the volunteers the same foods each week, the scientist ensured
that the volunteers produced that same amount of urine as each other per day.