That the geographic center of North America lay in the state of North Dakota was conceded by all ________ establishing...

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

• That the geographic center of North America lay in the state of North Dakota
  • was conceded by all involved(?);
• establishing its precise coordinates
  • proved more divisive.

Understanding the Meaning

Let's start reading from the beginning:

'That the geographic center of North America lay in the state of North Dakota'

• This is what the sentence is about - a fact about North America's geographic center being in North Dakota.

'was conceded by all involved'

• This tells us that everyone agreed on this point - there was no dispute about the center being in North Dakota.

So the first part gives us: everyone agreed that North Dakota contains the geographic center of North America.

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

• We're deciding what punctuation (if any) should come after 'involved'
• The options are: colon, comma, no punctuation, or semicolon

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

'establishing its precise coordinates proved more divisive'

• 'establishing its precise coordinates' - this means figuring out the exact latitude and longitude
• 'proved more divisive' - this means caused more disagreement or dispute

So this part tells us: when people tried to pin down the EXACT location with specific coordinates, that's when disagreement arose.

The complete picture:

• First statement: Everyone agreed North Dakota contains the center (no problem there)
• Second statement: But finding the precise coordinates caused disputes (this was controversial)

What do we notice about the structure here?

• The first part is a complete thought that could stand alone: 'That the geographic center...was conceded by all involved.'
  • It has a subject and verb
  • It expresses a complete idea
• The second part is also a complete thought that could stand alone: 'Establishing its precise coordinates proved more divisive.'
  • It has its own subject ('establishing its precise coordinates')
  • It has its own verb ('proved')
  • It expresses a complete idea
• These two complete thoughts are closely related - they're both about the same topic (the geographic center), and they present a contrast (agreement vs. disagreement)

When we have two complete thoughts that are closely related and we want to connect them without using a word like 'and' or 'but,' we need a semicolon to join them properly.

So we need: Choice D (involved;)

GRAMMAR CONCEPT APPLIED

Connecting Two Complete Thoughts with a Semicolon

When you have two complete sentences (called independent clauses in grammar terms) that are closely related in meaning, and you want to connect them without using a connecting word like 'and' or 'but,' you should use a semicolon:

Pattern:

• Complete thought 1 ; Complete thought 2

Example 1:

• The committee approved the budget; the project could finally begin.
• First part: "The committee approved the budget" (complete thought - has subject and verb)
• Second part: "the project could finally begin" (complete thought - has subject and verb)
• Related ideas connected with semicolon

Example 2:

• Students preferred the morning sessions; teachers found the afternoon ones more productive.
• Two contrasting but related complete thoughts
• Semicolon shows they're connected ideas without needing 'but' or 'however'

In our question:

• "That the geographic center...was conceded by all involved" (complete thought)
• "establishing its precise coordinates proved more divisive" (complete thought)
• These are closely related ideas about the same topic, presenting a contrast
• Semicolon properly connects them

Key distinction:

• Use a comma + and/but/so if you want to use a connecting word
• Use a semicolon if you're connecting them without a connecting word
• Don't use just a comma alone - that creates a comma splice error