Does anyone know what Complete sentence response mean?

The aim in writing is always to write in complete sentences which are correctly punctuated. Sentences always begin with a capital letter and end in either a full stop, exclamation or question mark. A complete sentence always contains a verb, expresses a complete idea and makes sense standing alone. A complex sentence is a sentence that contains an independent clause and one or more dependent clauses. An independent clause can stand alone as a sentence, but a dependent clause even though it has a subject and a verb cannot stand alone. Here are some examples of complex sentences.

Explanation:

industry had made the u.s. the richest nation in the world at this time. the second industrial revolution caused growth in industry and transportation, which allowed increased trade between nations.