Question

fix the adjective error (if one exists). because maxwell fair and i knew that a water balloon attack was coming, we were the alertest kids in the huddle.

Explanation:

The adjective "alertest" is incorrect. For the adjective "alert", the correct superlative form is "most alert" (used for adjectives of three or more syllables, or when the adjective does not follow the standard -est superlative rule).

Answer:

Because Maxwell Fair and I knew that a water balloon attack was coming, we were the most alert kids in the huddle.