Final answer:
The audience is an essential ingredient in live theatre as their presence energizes and complements the actors, provides feedback, and influences the rhythm and pace of the performance.
Step-by-step explanation:
An essential ingredient in live theatre is the audience. The presence of an audience is crucial for a live theatre performance as it energizes and complements the actors. The audience's reactions and engagement serve as a barometer for the success of a play and provide immediate feedback to the actors. Additionally, the audience's attentiveness and reaction contribute to the overall rhythm and pace of the production.