What type of sentence contains one independent clause and at least one dependent clause?

A complex sentence contains one 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 cannot stand alone and typically starts with a subordinating conjunction, such as "because," "although," or "since." This structure allows for more intricate expression of ideas, connecting a main idea with additional information or nuances. In contrast, the other types of sentences have different characteristics: a simple sentence contains only one independent clause, a compound sentence consists of two or more independent clauses joined by a conjunction, and a compound-complex sentence has multiple independent clauses along with at least one dependent clause. Thus, the definition of a complex sentence aligns perfectly with the description provided in the question.