Ecologists studying territorial behavior have explained why reintroduced wolf packs in the northern wilderness thrived while those in the southern...

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

• Ecologists studying territorial behavior
  • have explained
    • why reintroduced wolf packs in the northern wilderness thrived
    • while those in the southern region struggled [?]
      • the northern territory provided abundant elk populations
        • and minimal human development,
      • whereas the southern area had been fragmented by highways
        • and offered limited prey availability.

Understanding the Meaning

Let's start from the beginning:

'Ecologists studying territorial behavior have explained why reintroduced wolf packs in the northern wilderness thrived while those in the southern region struggled'

So we have scientists who study how animals claim and defend territories, and they've figured out why:

• Some reintroduced wolves (the ones in the northern wilderness) - thrived
• Other reintroduced wolves (those in the southern region) - struggled

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

• Choice A: no punctuation
• Choice B: a colon
• Choice C: a comma
• Choice D: adds the word 'while'

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

'the northern territory provided abundant elk populations and minimal human development, whereas the southern area had been fragmented by highways and offered limited prey availability.'

Now let's really understand what this is telling us:

• 'The northern territory provided abundant elk populations and minimal human development'
  • The northern area had lots of elk (which wolves hunt for food)
  • And it had very little human development (so wolves weren't disturbed)
• 'Whereas the southern area had been fragmented by highways and offered limited prey availability'
  • The southern area had been broken up by highways (disrupting wolf territory)
  • And it didn't have much prey for wolves to hunt

So the complete picture is:

• The first part says ecologists explained why some wolves thrived and others struggled
• The second part GIVES THAT EXPLANATION - it tells us the actual reasons

What do we notice about the structure here?

• Both parts are complete thoughts that could stand alone as sentences:
  • 'Ecologists have explained why...' = complete thought
  • 'The northern territory provided... whereas the southern area...' = complete thought
• The second part directly explains what the first part mentioned
  • First part: 'ecologists explained why...'
  • Second part: here's that explanation - the reasons why

When you have two complete thoughts and the second one explains or provides details about the first, you need a colon to connect them.

So we need: struggled:

The correct answer is Choice B.

GRAMMAR CONCEPT APPLIED

Using Colons to Connect Complete Thoughts When the Second Explains the First

When you have two complete thoughts (called independent clauses in grammar terms) and the second one explains, elaborates on, or provides specific details about the first, use a colon to connect them:

Pattern:

• Complete thought + colon + explanation/elaboration

Example 1:

• Statement: The experiment failed for a clear reason
• With explanation added: The experiment failed for a clear reason: the temperature controls malfunctioned during the critical phase
• First part = complete thought stating something happened
• Colon signals 'here comes the explanation'
• Second part = complete thought giving that explanation

Example 2:

• Statement: The athletes understood why they lost the championship
• With explanation added: The athletes understood why they lost the championship: their training regimen had focused on speed while their opponents had emphasized endurance
• First part = complete thought saying they understood
• Colon signals 'here's what they understood'
• Second part = complete thought providing those reasons

In our question:

• First part: 'Ecologists have explained why reintroduced wolf packs in the northern wilderness thrived while those in the southern region struggled'
  • Complete thought: says ecologists explained something
• Colon: signals 'here's that explanation'
• Second part: 'the northern territory provided abundant elk populations and minimal human development, whereas the southern area had been fragmented by highways and offered limited prey availability'
  • Complete thought: gives the actual reasons (good conditions vs. bad conditions)

The colon bridges these two complete thoughts by showing that the second directly explains or elaborates on the first.