Answer:
A group of words that includes a subject and verb and makes sense on its own is a sentence.
Explanation:
A complete sentence has to contain all of these things. It especially needs to make sense on its own.
A dependent clause contains a subject and verb, but does not make sense on its own.
A fragment looks like a sentence, but isn't. It doesn't contain an independent clause, which contains a subject and verb.
A comma splice is when a comma is not used to separate two independent clauses.
