The gas present in dough is carbon dioxide (CO2). It is produced by the action of yeast or baking powder, which releases the gas as they react with the ingredients in the dough.

* Yeast ferments sugars in the dough, producing carbon dioxide and alcohol as byproducts.

* Baking powder is a chemical leavening agent that reacts with moisture and heat to release carbon dioxide.

This carbon dioxide gets trapped in the gluten network of the dough, causing it to rise and become light and airy.