"Yeast," Sam said. "You know. Eukaryotic, single-celled microorganisms?" Okay, that probably wasn't helping. "Uh, a type of fungus. Causes fermentation. Converts carbohydrates to carbon dioxide and alcohols. Basically, it's what makes the potatoes not just potatoes any more."

There was a reason why Sam was better at the science than the teaching of science.

She offered the girl an apologetic shrug. "Sorry. I'm not the best at explaining."