Mitigate means to reduce or limit the harm caused by something. Using plenty of ice helped keep his sore muscles from getting worse. We were able to mitigate the traffic problems after the accident...
When it has a subject, verb, punctuation, capitalization, a predicate, and a complete thought. A sentence is a sentence when it is handed down by a judge (or a magistrate).
A sentence is a sentence because it has a subject (noun or noun phrase), a predicate ( verb) and punctuation as well as the other parts of speech like pronouns ( she, it him, her, they, them)...