Leah's parents are afraid the five-year-old will develop tooth decay if she chews gum that is sweetened with sugar. based on this information, leah's parents should buy chewing gum that is sweetened with

I believe the answer is: Xylitol

The bacteria that caused the tooth decay couldn't grow because xylitol prevent them from sticking on the teeth.

Xylito is considered as a form of natural sweetener that derived from the fibrous parts of plants.