Yeast and Mold are both types of fungi. Fungi are a group of organisms that include mushrooms, molds, and yeasts. Yeast is a single-celled organism that is used in baking and brewing, while mold is a multi-celled organism that can be found in nature and can cause food spoilage. Both yeast and mold are important components of the food industry, as they are used to produce food products such as bread, beer, and cheese.