Archaeologist Dr. Sarah Okonkwo led excavations at a medieval site in Ghana in 2018, uncovering artifacts that had been buried...

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

First sentence:

• Archaeologist Dr. Sarah Okonkwo led excavations at a medieval site in Ghana in 2018, uncovering artifacts that had been buried for over 600 years.

Second sentence:

• Once carefully extracted from the soil using specialized preservation techniques, (?) [what happens next]

Understanding the Meaning

Let's start reading from the beginning:

The first sentence tells us:

• Dr. Sarah Okonkwo led excavations at a medieval site in Ghana in 2018
• She uncovered artifacts that had been buried for over 600 years

Now the second sentence begins with:

• "Once carefully extracted from the soil using specialized preservation techniques,"

This is where we have the blank. This opening phrase is describing something being extracted from the soil. But what comes next?

Let's look at the choices - they vary in what subject comes after the comma:

• Choice A: "the artifacts were transported..."
• Choice B: "the research team transported..."
• Choice C: "Dr. Okonkwo and her team's transportation..."
• Choice D: "detailed analysis became possible..."

To see what works here, let's think about what this opening phrase is describing!

The phrase "Once carefully extracted from the soil using specialized preservation techniques" is describing something being extracted.

What was extracted from the soil? The artifacts.

What do we notice about the structure here?

• When a sentence starts with a phrase describing an action or state (like "Once extracted from the soil"), the thing being described needs to come right after the comma.
• If you put something else there, the sentence structure makes it sound like you're describing that other thing instead.
• Here, the opening phrase describes the artifacts being extracted
  • So "the artifacts" must be the subject immediately after the comma

So we need Choice A: "the artifacts were transported to a climate-controlled facility for detailed analysis."

This creates the proper connection:

• "Once [the artifacts were] carefully extracted from the soil, the artifacts were transported..."
• The artifacts = what was extracted = the subject after the comma (Correct)

Grammar Concept Applied

Placing Introductory Descriptive Phrases Correctly

When you start a sentence with a phrase that describes an action or condition (called an introductory modifying phrase in grammar terms), the thing being described must come immediately after the comma. If you put something else there, the sentence incorrectly suggests you're describing that other thing.

The pattern:

• [Phrase describing something], [the thing being described] + [rest of sentence]

Examples:

Correct: "After running five miles, Maria collapsed on the couch."

• "After running five miles" describes Maria
• Maria comes right after the comma (Correct)

Incorrect: "After running five miles, the couch was where Maria collapsed."

• "After running five miles" now seems to describe the couch
• The couch didn't run five miles (Incorrect)

How this applies to our question:

Correct: "Once carefully extracted from the soil using specialized preservation techniques, the artifacts were transported to a climate-controlled facility."

• "Once carefully extracted from the soil" describes the artifacts
• The artifacts come right after the comma (Correct)

Incorrect: "Once carefully extracted from the soil using specialized preservation techniques, the research team transported the artifacts to a climate-controlled facility."

• "Once carefully extracted from the soil" now seems to describe the research team
• The research team wasn't extracted from the soil (Incorrect)