What is the adjective in some snakes have colorful rings

Colorful is the adjective for the rings of the snakes. Colorful describes the look of the rings.

Explanation:

ad·jec·tive

/ˈajəktiv/

noun

a word or phrase naming an attribute, added to or grammatically related to a noun to modify or describe it.

Exp. The day was cloudy

The elegant lady went downstairs.

A dog that was fuzzy liked to run in puddles.

Adjectives describe nouns.