Here's why:

* Cellular Structure: Fungi, like animals, store energy as glycogen. Plants store energy as starch.

* Cell Walls: Fungi have cell walls made of chitin, which is also found in the exoskeletons of insects and other arthropods. Plants have cell walls made of cellulose.

* Nutrition: Fungi are heterotrophs, meaning they obtain their food from other organisms. They cannot produce their own food like plants. Animals are also heterotrophs.

* Genetic Evidence: Molecular studies comparing DNA and RNA sequences have shown that fungi are more closely related to animals than to plants.

While fungi share some similarities with both animals and plants, the evidence overwhelmingly supports a closer relationship to animals.