Why do fungi not belong to plants?

Answer 1

They are not producers and lack chlorophyll. They can not make their own food, though nether can some parasitic plants. Fungi have different cell walls than plants. Plants use cellulose to construct cells walls while fungi use chitin.

Answer 2

Fungi are a separate kingdom from plants because they have distinct cellular structures and modes of nutrition. Fungi are heterotrophic, meaning they cannot photosynthesize like plants do. Instead, they obtain nutrients by absorbing them from their environment. This difference in nutrition and cellular organization sets fungi apart as a unique kingdom in the classification of living organisms.