The life spans of rockfish vary greatly by species. For instance, the colorful calico rockfish (Sebastes dallii) can survive for...

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 life spans of rockfish vary greatly by species.
• For instance,
  • the colorful calico rockfish (Sebastes dallii)
    • can survive
      • for a little over a decade (?) while
        • the rougheye rockfish (Sebastes aleutianus)
          • boasts a maximum life span
            • of about two centuries.

Understanding the Meaning

Let's start reading from the beginning:

The first sentence sets up the topic:

• "The life spans of rockfish vary greatly by species."
  • So different types of rockfish live for very different amounts of time.

Now the passage gives us specific examples:

• "For instance, the colorful calico rockfish (Sebastes dallii) can survive for a little over a decade"
  • One type lives for just over 10 years.

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

• We're deciding between different punctuation marks (colon, period, semicolon, or comma)
• And whether "while" should be capitalized or not

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

• "while the rougheye rockfish (Sebastes aleutianus) boasts a maximum life span of about two centuries"
  • A different type of rockfish can live for about 200 years!

So the complete picture is:

• The passage is contrasting two very different lifespans
  • Calico rockfish: just over a decade
  • Rougheye rockfish: about two centuries
• The word "while" here means "whereas" – it's showing the contrast between these two fish

What do we notice about the structure here?

• We have two parts being contrasted in a single sentence:
  • First part: "the colorful calico rockfish can survive for a little over a decade"
    • This is a complete thought
  • Second part: "while the rougheye rockfish boasts a maximum life span of about two centuries"
    • This is the contrasting information, introduced by "while"
• These two contrasting pieces belong together in one sentence
  • They're comparing the lifespans side by side
  • "While" (meaning "whereas") is connecting them

When you're joining two parts of a sentence with a contrasting word like "while," you use a comma before it.

So we need: comma + lowercase "while" → Answer D

GRAMMAR CONCEPT APPLIED

Using Commas with Contrasting Conjunctions

When you want to contrast two pieces of information within a single sentence using "while" (meaning "whereas"), you place a comma before "while":

Pattern:

• First statement + comma + while + contrasting statement

Example 1:

• "The first method is quick and easy, while the second method is slow but more accurate."
• First statement: The first method is quick and easy
• Comma signals the contrast is coming
• "While" introduces the contrasting information
• Second statement: the second method is slow but more accurate

Example 2:

• "Some students prefer studying in groups, while others work better alone."
• The comma before "while" connects two contrasting preferences

In our question:

• "The colorful calico rockfish can survive for a little over a decade, while the rougheye rockfish boasts a maximum life span of about two centuries."
• First statement: calico rockfish lives just over 10 years
• Comma + "while" signals the contrast
• Second statement: rougheye rockfish lives about 200 years
• The comma properly joins these contrasting lifespans in one sentence