Here's why:

* Fungi are generally multicellular: Most fungi are made up of thread-like structures called hyphae, which intertwine to form a network called a mycelium.

* Yeasts are unicellular: They are single-celled organisms that reproduce through budding, where a new cell grows from a parent cell.

While yeasts are not multicellular, they are still classified as fungi. They share many characteristics with other fungi, such as their cell walls made of chitin and their ability to obtain nutrients through absorption.