The Mesoamerican city of Teotihuacan featured a uniquely egalitarian urban housing infrastructure. Built between the first and seventh centuries CE,...

Let's begin by understanding the meaning of this sentence. We'll use our understanding of pause points and segment the sentence as shown - understanding and assimilating the meaning of each segment bit by bit!

Sentence Structure

• The Mesoamerican city of Teotihuacan
  • featured a uniquely egalitarian urban housing infrastructure.
• Built between the first and seventh centuries CE,
  • Teotihuacan
    • housed its residents
      • (as many as 200,000,
        • by some estimates?)
    • in a complex of comfortable apartments of comparable size.

Understanding the Meaning

Let's start from the beginning:

The first sentence sets the stage:

• 'The Mesoamerican city of Teotihuacan featured a uniquely egalitarian urban housing infrastructure.'
  • This city had a housing system that was unusually fair and equal for everyone.

Now the second sentence gives us the details:

• 'Built between the first and seventh centuries CE, Teotihuacan housed its residents...'
  • We're learning about when it was built and what it did for its people.

Then we get some extra information in parentheses:

• '(as many as 200,000, by some estimates____'
  • This is an aside - additional detail about HOW MANY residents lived there.
  • 'By some estimates' means this is an approximation from historians or scholars.

This is where we have the blank. Let's look at the choices:

• Choice A: estimates)
• Choice B: estimates),
• Choice C: estimates—
• Choice D: estimates

To see what works here, let's read the rest of the sentence and understand what it's saying!

• 'in a complex of comfortable apartments of comparable size.'
  • The residents lived in apartment complexes
  • The apartments were comfortable and similar in size - supporting that "egalitarian" idea

Now, what do we notice about the structure here?

• The phrase 'as many as 200,000, by some estimates' is tucked inside the main sentence as extra information
  • It starts with an opening parenthesis: (
  • This means it MUST end with a closing parenthesis: )
• Parentheses work in pairs - you can't have one without the other
  • Just like quotation marks or brackets
  • If you open with (, you must close with )
• After we close the parenthesis, does the sentence need a comma?
  • Let's read it without the parenthetical: 'Teotihuacan housed its residents in a complex of comfortable apartments'
  • The phrase 'in a complex' flows naturally right after 'residents'
  • No comma needed - there's no pause or grammatical reason for one

So we need: estimates) - just the closing parenthesis with no additional punctuation.

The correct answer is Choice A.

GRAMMAR CONCEPT APPLIED

Matching Pairs: Parentheses Must Be Paired Correctly

When you insert parenthetical information (extra details or asides) into a sentence using parentheses, you must follow this rule:

Opening parenthesis ( must be matched with closing parenthesis )

This is similar to how quotation marks work - you can't start with one type and end with another:

• Correct: The city (which was very large) had many residents
• Incorrect: The city (which was very large— [mixing punctuation types]
• Incorrect: The city (which was very large [leaving it unpaired]

What about commas after closing parentheses?

Whether you need a comma after a closing parenthesis depends on the sentence structure itself, NOT on the fact that you used parentheses:

• Example 1 (no comma needed): The researcher studied birds (especially sparrows) in urban areas
  • "in urban areas" flows naturally after "birds"
• Example 2 (comma needed): The researcher studied birds (especially sparrows), and she published her findings
  • The comma is needed because "and she published" starts a new independent clause
  • The comma would be there even without the parentheses: "The researcher studied birds, and she published her findings"

In our question:

• "housed its residents (as many as 200,000, by some estimates) in a complex of comfortable apartments"
• Reading without parentheses: "housed its residents in a complex"
• No pause or grammatical break needed → no comma after the closing parenthesis