How do scientists determine what foods were eaten by extinct hominins such as Neanderthals? In the past, researchers were limited...

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

• How do scientists determine what foods were eaten by extinct hominins
  • such as Neanderthals?

• In the past,
  • researchers were limited to studying the marks
    • found on the fossilized teeth of skeletons,
• but in 2017
  • a team
    • led by Laura Weyrich of the Australian Centre for Ancient DNA
  • tried something new[?] sequencing the DNA
    • found in Neanderthals' fossilized dental plaque.

Understanding the Meaning

The passage starts with a question about how scientists figure out what extinct hominins like Neanderthals ate.

Then we get the answer in the second sentence:

• 'In the past, researchers were limited to studying the marks found on the fossilized teeth of skeletons'
  • So the old method was looking at tooth marks

• 'but in 2017 a team led by Laura Weyrich of the Australian Centre for Ancient DNA tried something new'
  • Now we're contrasting with a NEW method that came along in 2017
  • This team tried "something new" – but what was it?

This is where we have the blank.

Let's look at the choices:

• A gives us a colon
• B gives us a semicolon
• C gives us a comma, then puts a colon later
• D gives us a period and starts a new sentence

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

• 'sequencing the DNA found in Neanderthals' fossilized dental plaque'
  • This tells us the specific NEW thing they tried
  • They sequenced DNA from dental plaque (the buildup on teeth)

Now let's understand the relationship between these two parts:

• 'tried something new'
  • This is telling us they attempted a new approach
  • But it's vague – we don't know WHAT the new thing was yet

• 'sequencing the DNA found in Neanderthals' fossilized dental plaque'
  • This explains WHAT that "something new" was
  • It's giving us the specific details

What do we notice about the structure here?

• The first part is a complete statement: "tried something new"
  • It works grammatically, but leaves us wondering what the new thing was

• The second part explains or specifies what that new thing was
  • It's answering the question: "What was the something new?"
  • This is exactly what needs a colon – when you're about to explain or specify something you just mentioned

• The second part "sequencing the DNA..." is NOT a complete sentence on its own
  • It's a descriptive phrase, not a standalone thought

So we need a colon to signal "here's what that new thing was."

The correct answer is Choice A: new: sequencing

GRAMMAR CONCEPT APPLIED

Using Colons to Introduce Explanations

When you make a complete statement that mentions something general or vague, you can use a colon to introduce the specific explanation or elaboration of what you just mentioned. The key pattern is:

[Complete statement] : [explanation/specification of something in that statement]

Example 1:

• Statement: "The researchers discovered something surprising"
• With colon: "The researchers discovered something surprising: fossil evidence of ancient cooking fires"
• The part after the colon explains WHAT the surprising thing was

Example 2:

• Statement: "The experiment required specialized equipment"
• With colon: "The experiment required specialized equipment: a mass spectrometer and an electron microscope"
• The part after the colon specifies WHAT equipment was needed

In our question:

• Statement: "tried something new"
• With colon: "tried something new: sequencing the DNA found in Neanderthals' fossilized dental plaque"
• The part after the colon tells us exactly WHAT that new thing was

Important note: The part before the colon must be a complete statement (what grammarians call an independent clause). The part after the colon can be a phrase, list, or another complete statement – whatever provides the explanation.