Answers:
Fragments
A fragment is a group of words that "does not" express a complete thought. Correct a fragment by turning it into a complete sentence that states a complete thought.
A complete sentence (or independent clause) is a group of words that:
a) contains a subject and a verb
b) expresses a complete thought
A dependent clause contains a subject and a verb but does not express a complete thought. Dependent clauses are fragments, unless they are attached to a clause expressing a complete thought. In this sentence, "unless they are attached to a clause expressing a complete thought" is a dependent clause. If that clause were written as if it were a sentence, that would be a sentence fragment.