In 2019, marine biologists confirmed the presence of a new species in the Arctic ______ shy creature, it had evaded...

Sentence Structure

• In 2019,
  • marine biologists
    • confirmed the presence of a new species
      • in the Arctic Ocean [?] the sixgill shark [?] [a/A]
        • shy creature,
          • it had evaded detection for decades
            • by dwelling in the deepest trenches,
              • where extreme pressure and darkness
                • provided protection
                  • from both predators and scientific observation.

Understanding the Meaning

Let's start reading from the beginning:

In 2019, marine biologists confirmed the presence of a new species in the Arctic Ocean

• This tells us about a discovery - marine biologists found a new species in the Arctic Ocean in 2019

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

• What punctuation comes after "Ocean"
• What punctuation comes after "the sixgill shark"
• Whether we have lowercase "a" or capital "A"

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

The sentence continues: "the sixgill shark, a shy creature, it had evaded detection for decades by dwelling in the deepest trenches, where extreme pressure and darkness provided protection from both predators and scientific observation."

Now let's really understand what this is telling us. Let me break down the parts:

• "the sixgill shark"
  • This is identifying WHAT the new species is
  • It's giving us the specific name after mentioning "a new species"
• "a shy creature, it had evaded detection for decades by dwelling in the deepest trenches..."
  • "a shy creature" is describing this shark
  • "it had evaded detection for decades" is telling us what this creature did - it avoided being discovered for a long time
  • "by dwelling in the deepest trenches" explains HOW it avoided detection - by living in the deep parts of the ocean
  • "where extreme pressure and darkness provided protection" explains why those deep trenches were such a good hiding spot

So the complete picture is:

• First part: Marine biologists discovered a new species → we need to identify which one
• Second part: That species is the sixgill shark
• Third part: This shy shark avoided detection for decades by living in extreme deep-water conditions

What do we notice about the structure here?

• After "Arctic Ocean," we've made a complete statement about a discovery
  • The next part "the sixgill shark" identifies what that species is
  • This is introducing a specific identification or explanation
• "A shy creature, it had evaded detection..." is actually a complete sentence on its own
  • "A shy creature" is a descriptive phrase introducing the subject
  • "it had evaded detection..." is a complete independent clause with its own subject and verb

So we need:

• A colon after "Ocean" to introduce the specific identification
• A period after "shark" to separate two complete sentences
• Capital "A" to start the new sentence

The correct answer is Choice B: Ocean: the sixgill shark. A

This creates two properly structured sentences:

• Sentence 1: "In 2019, marine biologists confirmed the presence of a new species in the Arctic Ocean: the sixgill shark."
• Sentence 2: "A shy creature, it had evaded detection for decades by dwelling in the deepest trenches, where extreme pressure and darkness provided protection from both predators and scientific observation."

GRAMMAR CONCEPT APPLIED

Using Colons to Introduce Identifications and Managing Sentence Boundaries

When you've mentioned something general and want to specify exactly what it is, a colon works perfectly to introduce that identification. Additionally, you need to recognize when you have complete, independent sentences that should be separated.

Pattern for Colons Introducing Identifications:

• General statement: specific identification
  • The statement before the colon is a complete sentence
  • What follows the colon identifies or explains something specific

Example 1:

• "The researchers discovered a new element: francium."
  • Before colon: complete sentence about a discovery
  • After colon: the specific identification

Example 2:

• "She had one goal: winning the championship."
  • Before colon: complete sentence about having a goal
  • After colon: what that specific goal is

In this question:

• "Marine biologists confirmed the presence of a new species in the Arctic Ocean: the sixgill shark."
  • Before colon: complete sentence about confirming a new species
  • After colon: which species it is

Pattern for Sentence Boundaries:

When you have a complete independent sentence (with its own subject and verb), it should be separated from other complete sentences with a period, not connected with just commas.

• "A shy creature, it had evaded detection for decades..."
  • This is a complete sentence: "it" is the subject, "had evaded" is the verb
  • It needs to stand as its own sentence, separate from what came before