Logic is used to invent, prove, or demonstrate a(n)
description
argument
theme

The answer is Argument

Explanation:

Logic in writing is a system of analysis that writers use to invent, demonstrate and prove arguments. There exist two types of logical arguments: Deductive and Inductive. The deductive argument gives the entire evidence and its conclusion, while the Inductive argument gives a generalization of reasoning that could not be accurate.

to gain popularity at school, fitzgerald wrote plays for the school and cast himself as the star. he also joined one of the universitys most prestigious clubs.