The Topic: Lucy and Ethel make me wonder

Yeast, a single celled fungal cell, converts sugar to usable energy through a magical process called anaerobic respiration. Sugar in the dough is converted to alcohol and carbon dioxide. The carbon dioxide causes the dough to rise.

Uh, what does the alcohol do?

It evaporates during baking

All the more reason to stick your head in an oven, folks.