What is the difference between baking soda and baking powder and yeast?

Yeast, like baking soda (and baking powder), is used to leavened baked goods . The difference between these leavening agents is that baking powder/soda react chemically to produce the carbon dioxide that makes the baked goods rise. Yeast, on the other hand, is a living organism and the carbon dioxide it produces is the result of the yeast feeding on the dough.

When yeast is used in baked goods it not only increases the volume but also improves the texture, grain and flavor of the bread.