उत्तर : 3. "रोटी पकाना रस "
व्याख्या :

Baking soda and baking powder help in baking bread. The microbe responsible for baking bread is a fungus named Saccharomyces cerevisiae for this reason it is also called baker's yeast. Hence, from the above-mentioned points, it becomes clear that bacteria are not used in the baking of bread.