Unearthed from a limestone deposit in rural Montana and meticulously analyzed using advanced radiometric dating techniques, ______ reveals unprecedent...

Sentence Structure

• Unearthed from a limestone deposit in rural Montana
• and
• meticulously analyzed using advanced radiometric dating techniques,
• ______ [varies: person/fossil/discovery as subject]
• reveals unprecedented details
  • about the skeletal structure
    • of one of the earliest known flying reptiles.

Understanding the Meaning

Let's start reading from the beginning:

'Unearthed from a limestone deposit in rural Montana and meticulously analyzed using advanced radiometric dating techniques,'

This opening phrase is describing something that had two things happen to it:

• It was unearthed (dug up) from a limestone deposit in Montana
• It was analyzed using dating techniques

Now, what kind of thing can be 'unearthed' and 'analyzed'?

• These actions describe something being dug up from the ground and scientifically examined
• This sounds like it's describing a fossil, not a person

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

• Choice A: starts with 'paleontologist Dr. James Morrison'
• Choice B: starts with 'the fossil'
• Choice C: starts with 'Dr. James Morrison'
• Choice D: starts with 'when paleontologist Dr. James Morrison...'

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

The sentence continues: '______ reveals unprecedented details about the skeletal structure of one of the earliest known flying reptiles.'

So whatever fills the blank is doing the revealing - it's showing us details about an ancient flying reptile's skeleton.

Now, what do we notice about the structure here?

• The opening phrase describes something being 'unearthed' and 'analyzed'
  • These are actions done TO something physical - to a fossil
  • You can't 'unearth' a person from the ground
• In English, when you start a sentence with a descriptive phrase like this,
  • whatever comes right after the comma must be the thing you're describing
  • The opening is describing a fossil being dug up and analyzed
  • So 'the fossil' needs to come immediately after the comma
• Looking at our choices:
  • Choice B puts 'the fossil' right after the comma
  • This matches perfectly - the fossil was unearthed, the fossil was analyzed, and the fossil reveals details

So we need Choice B: 'the fossil discovered by paleontologist Dr. James Morrison'

The complete sentence tells us: A fossil was dug up in Montana and analyzed, and this fossil (discovered by Dr. Morrison) reveals important details about early flying reptiles.

GRAMMAR CONCEPT APPLIED

Matching Opening Descriptive Phrases to the Right Subject

When a sentence begins with a descriptive phrase (called an introductory modifier in grammar terms) set off by a comma, whatever comes immediately after that comma must be the thing being described:

Pattern:

• [Descriptive phrase about something], [that something] + [rest of sentence]

Example 1:

• Wrong: 'Discovered in 1922, archaeologist Howard Carter found King Tut's tomb'
• This says the archaeologist was discovered in 1922
• Correct: 'Discovered in 1922, King Tut's tomb revealed amazing treasures'
• The tomb was discovered in 1922

Example 2:

• Wrong: 'Written in the 1850s, many students read Whitman's poetry today'
• This says the students were written in the 1850s
• Correct: 'Written in the 1850s, Whitman's poetry is still read by students today'
• The poetry was written in the 1850s

In this question:

• Opening phrase: 'Unearthed from a limestone deposit...and meticulously analyzed...'
• These words describe something physical being dug up and studied
• What must come next: 'the fossil'
• The fossil was unearthed, the fossil was analyzed
• Why Choice B works: It places 'the fossil' immediately after the comma, creating the logical connection

The key is asking yourself: What is being described by the opening words? Whatever your answer is must come right after the comma.