Sentences can be multiple clauses or just one, depending on the type.
A dependent clause cannot stand alone, though they often contain both a subject and a verb.
Where independent clauses express complete thoughts, dependent clauses do not, and left on their own, dependent clauses create fragments.
Ex:
An independent clause is basically a complete sentence; it can stand on its own. It consists of a subject (e.g. “The dog”) and a predicate (e.g. “barked”).
A simple sentence consists of an independent clause on its own.
Complex sentences combine independent (or main) and dependent (or subordinate) clauses.
A compound sentence consists of two or more simple sentences or independent clauses.
Compound-complex sentences combine a compound with a complex sentence.