Solution:

Yeast is the smallest fungi. Yeast is single-celled microorganisms that are classified, along with moulds and mushrooms, as members of the Kingdom Fungi. Yeasts are evolutionally diverse and are therefore classified into two separate phyla, Ascomycota or sac fungi and Basidiomycota or higher fungi, that together form the subkingdom Dikarya.

Yeast keeps your digestive system healthy and in balance. The right amount in your body helps your immune system do its job. Yeast is part of a healthy mix of bacteria in your gut. It can help you absorb vitamins and minerals from your food, and even fight disease.