Question

why does bread have small holes in it? 20 from the carbon dioxide given off from the yeast from the ethanol given off from the yeast due to oxygen given off from the yeast

Explanation:

Yeast undergoes fermentation in bread dough, producing carbon dioxide ($\ce{CO_2}$) gas. This gas gets trapped in the dough, creating bubbles that form the small holes when the bread bakes. Ethanol evaporates during baking, and yeast doesn't produce oxygen in this context. So the correct reason is the carbon dioxide from yeast.

Answer:

From the carbon dioxide given off from the yeast