What is a common food source for yeast?

Yeast is a type of fungus that primarily feeds on sugars. In the context of baking and fermentation, sugars serve as the main energy source for yeast cells, allowing them to grow, reproduce, and produce carbon dioxide and alcohol as byproducts. This process is essential in bread-making, where the carbon dioxide produced by yeast causes the dough to rise, resulting in a light and airy texture.

While fibers, starches, and meats contain carbohydrates and proteins, respectively, they are not the primary food source for yeast. Starches, for example, must first be broken down into sugars before yeast can utilize them. Thus, sugars are the most direct and effective source of nutrition for yeast, making them the correct answer in this context.