What distinguishes a complex sentence?

A complex sentence is distinguished by its combination of an independent clause and at least one dependent clause. The independent clause expresses a complete thought and can stand alone as a sentence, while the dependent clause, which begins with a subordinating conjunction (such as because, although, or if), cannot stand alone and provides additional information to the independent clause. This structure allows complex sentences to convey more detailed ideas by incorporating subordinate information that enhances the primary message.

The other options do not accurately describe the nature of complex sentences. For instance, the description of having two or more independent clauses pertains to a compound sentence. Stating that a complex sentence is always a question misidentifies its structure, as complex sentences can be declarative, interrogative, exclamatory, or imperative. The idea that a complex sentence is made up of two simple sentences also inaccurately represents the structure, as those would instead form compound sentences if they are combined without a dependent clause.