What does yeast use to make bread dough rise?

Yeast uses sugar to make bread dough rise. Here's how it works:

1. Yeast eats sugar: Yeast is a living organism and it feeds on sugar (specifically glucose).

2. Fermentation: As yeast consumes sugar, it produces carbon dioxide (CO2) and alcohol as byproducts.

3. Trapped gas: The CO2 gas gets trapped within the gluten network of the dough.

4. Expansion: The trapped gas causes the dough to expand and rise.

This process is called fermentation, and it's what gives bread its airy and light texture.