Assertion (A): Yeast is used in bakeries to make bread and cakes.
Reason (R): Yeast are added to the dough to produce carbon dioxide which makes the dough rise by fermentation process.
Both A and R are true and R is the correct explanation of A.
Saccharomyces cerevisiae, also known as baker's yeast, has been a key ingredient in baking because it converts sugars and starches into alcohol and carbon dioxide during the fermentation process.