What happens during the exposition of a fugue?

The exposition is the initial section of a fugue during which the principal theme, known as the subject, is stated successively in each of the constituent voices.1

The process typically follows these steps:
* First Statement: One voice begins by stating the subject alone.1
* The Answer: As the first voice continues, a second voice enters with the subject transposed to the dominant key (the fifth degree of the scale). This statement is called the answer.1
* Subsequent Statements: The third statement of the subject returns to the main key, while a fourth statement, if present, typically returns to the dominant key.1

During these entries, the subject is often accompanied by counterpoint in another voice. If this accompanying melody systematically recurs alongside the subject throughout the piece, it is labeled a countersubject. Otherwise, the accompanying counterpoint is considered free.1