The Mission 66 initiative, which was approved by Congress in 1956, represented a major investment in the infrastructure of overburdened...

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 Mission 66 initiative,
• which was approved by Congress in 1956,
• represented a major investment in the infrastructure of overburdened national parks [?]
  • it prioritized physical improvements to the parks' roads, utilities, employee housing, and visitor facilities

Where [?] =

• Choice A: 'and'
• Choice B: nothing
• Choice C: ';'
• Choice D: ','

Understanding the Meaning

Let's start reading from the beginning: The Mission 66 initiative (with a quick note that it was approved by Congress in 1956) represented a major investment in the infrastructure of overburdened national parks.

• This initiative was a big investment to help national parks that were struggling with too many visitors and not enough infrastructure.

Now we've reached the blank. This is where we have the blank after 'parks.'

Let's look at the choices:

• Choice A adds 'and'
• Choice B adds nothing
• Choice C adds a semicolon
• Choice D adds a comma

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

The next part says: 'it prioritized physical improvements to the parks' roads, utilities, employee housing, and visitor facilities while also establishing educational programming for the public.'

• What the initiative actually did - it focused on improving concrete things like roads and buildings
• It also set up educational programs

What do we notice about the structure here?

• Before the blank, we have a complete thought:
  • 'The Mission 66 initiative...represented a major investment in the infrastructure of overburdened national parks.'
  • This could stand alone as its own sentence.
• After the blank, we have another complete thought:
  • 'it prioritized physical improvements to the parks' roads, utilities, employee housing, and visitor facilities while also establishing educational programming for the public.'
  • This could also stand alone as its own sentence - it has its own subject ('it') and verb ('prioritized').

So we have two complete thoughts that need to be properly connected.

The correct answer is Choice C (semicolon).

A semicolon is specifically designed to join two complete thoughts that are closely related - and these two thoughts are definitely related (the second explains what the investment mentioned in the first actually involved).

GRAMMAR CONCEPT APPLIED

Joining Two Complete Thoughts

When you have two complete thoughts (called independent clauses in grammar terms) that could each stand alone as sentences, you have several options for connecting them, but you must use proper punctuation:

Option 1 - Semicolon (what we need here):

• Use when the thoughts are closely related
• Example: The initiative was expensive; it cost millions of dollars.
  • First complete thought: 'The initiative was expensive'
  • Second complete thought: 'it cost millions of dollars'
  • Semicolon joins them because they're related ideas

Option 2 - Period:

• Makes them separate sentences
• Example: The initiative was expensive. It cost millions of dollars.

Option 3 - Comma + Connecting Word:

• Use comma with words like 'and,' 'but,' 'so,' 'for,' 'or,' 'yet,' 'nor'
• Example: The initiative was expensive, and it cost millions of dollars.

What you CANNOT do:

• Just a comma: Creates a comma splice
  • Wrong: 'The initiative was expensive, it cost millions of dollars.'
• Nothing: Creates a run-on sentence
  • Wrong: 'The initiative was expensive it cost millions of dollars.'

In our question:

• First complete thought: 'The Mission 66 initiative...represented a major investment'
• Second complete thought: 'it prioritized physical improvements...'
• Solution: Semicolon joins these closely related thoughts