Answer
Vitamin C does indeed prevent colds and can be used to treat colds. This is because groups 2 and 4 had the fewest colds as Vitamin C was given as prevention. Likewise, groups 3 and 4 had the shortest colds as Vitamin C was given as therapy.
Work Step by Step
1. First, analyze the table to determine which combinations of placebo and Vitamin C produced the fewest colds.
2. Then, analyze the table to determine which combinations of placebo and Vitamin C produced the shortest colds.
3. Determine what the groups with either the fewest or shortest colds had in common.
4. Arrive at the conclusion that Vitamin C aids in both preventing colds and reducing their duration.
