Which substance makes bread rise?

Here's how it works:

* Yeast: Yeast is a type of fungus that feeds on sugar. As it eats, it produces carbon dioxide as a byproduct.

* Baking Soda/Baking Powder: These are chemical leavening agents that release carbon dioxide when mixed with moisture and heat.

The carbon dioxide gets trapped within the dough, creating bubbles that expand as the bread bakes. This expansion causes the bread to rise.