Some fungi are parasitic. They can destroy entire crops of plants like wheat and corn. There are scientists that study fungi called mycologists. Fungi are high in protein and Vitamin B. Yeast is known for mostly one thing. It is responsible for making bread rise and producing alcohol in beer and wine.
Yeast is said to have first been noticed when an Egyptian bread maker was making bread for the king.
He got lazy and fell asleep. When he woke up the bread was fluffy and collapsible. It was this way because it was left out and yeast landed on it. Enzymes trigger the chemical change. It is a change from starch to complex sugars to simple sugars to alcohol.