Final answer:
Betsy's hands became sweaty from the physical exertion and nervousness of sliding down the slide, which is a natural bodily response for temperature regulation.
Step-by-step explanation:
When Betsy slid down the slide at the park and held onto the sides the whole way down, she likely noticed that her hands were sweaty. This condition is a natural response to physical exertion or nervousness, leading to increased perspiration to help regulate body temperature. The friction from holding onto the slide, combined with the anxiety of sliding down, could contribute to this condition.