Yeast is a single-celled fungus, sometimes also referred to as yeast powder, that is, processed dormant yeast;\x0d\Baking powder in a broad sense is divided into biological baking powder and chemical baking powder. Baking powder is generally yeast powder. Chemical baking powder includes baking soda (sodium bicarbonate), alum (potassium aluminum sulfate), ammonium alum (ammonium aluminum sulfate), stink powder (ammonium bicarbonate), baking powder (alum and baking soda), etc. mixture) etc. \x0d\Their principle is to generate gas to expand the dough. \x0d\Active dry yeast is generally used to make bread. Wet yeast can also be used if conditions permit. Making bread is a technical job.