Explain the subject-verb agreement rule that applies to a singular collective subject functioning as a single unit. demonstrate your understanding of the rule by composing a sentence that uses the singular collective subject "audience."

Even though a collective noun may be something that is comprised of many things, those things (whatever they may be), collectively, make up one thing. Thus, for proper subject-verb agreement, collective nouns will require a singular noun. Let’s look at the following sentence and note how the singular collective noun “audience” is paired with the singular verb “laughs.”

The audience laughs at all the right moments.

Thus, even though an audience will typically have more than one person, it is only one audience and will require a singular verb in order to avoid a subject-verb agreement error.

and your question what topic are you in trouble with?