Here's why:
* Adjectives describe nouns or pronouns.
* Example: "The different colors of the rainbow" (describes the noun "colors").
* Verbs show action or a state of being.
* Example: "I differ with your opinion." (shows action)
* Prepositions show the relationship between a noun or pronoun and another word in the sentence.
* Example: "I walked different to the store." (This sentence is grammatically incorrect because "different" is not a preposition.)
Let me know if you have any other questions!