Answer:
The element that complete the graphic organizer is Independent Clause.
Independent Clause + Independent Clause=Compound sentence.
Step-by-step explanation:
A sentence containing at least two independent clauses together with a semicolon, comma or conjunctions is a compound sentence.
A clause that has both a subject and a verb to form a complete sentence is an Independent clause.
To add a clear meaning to a given sentence, the coordinators; comma, semicolon or conjunctions are required. Examples are, for, or, and, so, yet, but, etc.
Therefore, what makes a compound sentence what it is, is the presence of two independent clauses.