The DNA sequencing project, launched with funding from seven international _____ or the Global Microbiome Diversity Initiative, as researchers commonl...

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 DNA sequencing project,
• launched with funding from seven international agencies [?]
• or the Global Microbiome Diversity Initiative,
• as researchers commonly referred to it—
  • has produced unprecedented insights
  • into bacterial evolution across diverse ecosystems.

[?] = comma / nothing / em dash / colon

Understanding the Meaning

Let's start reading from the beginning:

The sentence is about:

• 'The DNA sequencing project'
  • This is what the sentence is discussing - a specific scientific project.

Then we get background information about this project:

• 'launched with funding from seven international agencies'
  • This tells us how the project got started - it was funded by seven international agencies working together.

This is where we have the blank after "agencies."

Let's look at the choices:

• We're deciding between: comma, no punctuation, em dash, or colon after "agencies"

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

After the blank, the sentence continues:

• 'or the Global Microbiome Diversity Initiative'
  • The word "or" signals this is an alternative name
  • So the seven agencies together were also known as "the Global Microbiome Diversity Initiative"

Then we get additional clarification:

• 'as researchers commonly referred to it—'
  • This confirms that "the Global Microbiome Diversity Initiative" is what researchers called this group of agencies
  • Notice this phrase ends with an em dash (—)

Then the sentence completes its main point:

• 'has produced unprecedented insights into bacterial evolution across diverse ecosystems'
  • This tells us what the project accomplished

What do we notice about the structure here?

The phrase "or the Global Microbiome Diversity Initiative, as researchers commonly referred to it" is an interruption:

• It's inserted into the middle of the main sentence
• It provides an alternative name/clarification
• The main sentence would read: "The DNA sequencing project... has produced unprecedented insights"

Now here's the key:

• This interrupting phrase ENDS with an em dash (—)
• When you use dashes to set off an interrupting phrase, you need MATCHING punctuation on BOTH sides
• Just like bookends - you need one dash to open the interruption and one dash to close it

So we need: agencies— to match the closing dash after "referred to it—"

The correct answer is Choice C: agencies—

GRAMMAR CONCEPT APPLIED

Paired Punctuation for Interrupting Phrases

When you insert an interrupting or clarifying phrase into the middle of a sentence, you must use matching punctuation marks on both sides to set it off. These interrupting phrases (called parenthetical elements in grammar terms) can be enclosed by:

Three options - but they must match:

• Both commas
• Both em dashes (—)
• Both parentheses

Example 1 - Using paired commas:

• The scientist, a expert in marine biology, discovered a new species
  • Opening comma before the interruption
  • Closing comma after the interruption

Example 2 - Using paired dashes:

• The scientist—an expert in marine biology—discovered a new species
  • Opening dash before the interruption
  • Closing dash after the interruption

When to prefer em dashes over commas:

• When the interruption already contains commas internally
• When you want to emphasize the inserted information
• When the interruption is substantial or significant

In our question:

• The phrase "or the Global Microbiome Diversity Initiative, as researchers commonly referred to it" is the interruption
• It already contains a comma internally ("Initiative, as researchers")
• The sentence shows the closing em dash (—) after "referred to it"
• Therefore, we need the opening em dash after "agencies" to create the matching pair

The complete structure: "agencies—or the Global Microbiome Diversity Initiative, as researchers commonly referred to it—has produced"