Marine biologist Sylvia Earle has been a pioneering force in ocean ______ demonstrated by her record-breaking deep-sea dives and establishment...

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

• Marine biologist Sylvia Earle
  • has been a pioneering force in ocean conservation [?]
    • demonstrated by her record-breaking deep-sea dives
      • and establishment of marine protected areas worldwide,
  • Earle's impact on ocean conservation
    • has been unprecedented in both scope and influence.

Understanding the Meaning

Let's start reading from the beginning:

'Marine biologist Sylvia Earle has been a pioneering force in ocean conservation'

• We're learning about Sylvia Earle
• She's a marine biologist
• She has been a pioneering force - meaning she's been a leader and innovator
• Specifically in ocean conservation

This is a complete thought - we have a subject (Sylvia Earle), what she's been doing (has been), and what she's been (a pioneering force).

This is where we have the blank.

Let's look at the choices:

• A gives us "and as"
• B gives us a period and capital "As" (two sentences)
• C gives us a comma and "as"
• D gives us just "as" with no punctuation

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

'as demonstrated by her record-breaking deep-sea dives and establishment of marine protected areas worldwide, Earle's impact on ocean conservation has been unprecedented in both scope and influence.'

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

• 'As demonstrated by her record-breaking deep-sea dives and establishment of marine protected areas worldwide'
  • This is explaining HOW we know about her pioneering force
  • It's giving us evidence: record-breaking dives and creating protected areas
  • This phrase starting with "As" is an introductory clause

• Then after a comma: 'Earle's impact on ocean conservation has been unprecedented in both scope and influence'
  • Now we have a new subject: "Earle's impact"
  • With its own verb: "has been"
  • Telling us something: her impact has been unprecedented (never seen before)
  • In both scope (how far-reaching) and influence (how much effect)

What do we notice about the structure here?

• The part before the blank is a complete thought:
  • "Sylvia Earle has been a pioneering force in ocean conservation"
  • This could stand alone as a sentence

• The part after the blank is ALSO a complete thought:
  • Starting with an introductory phrase "As demonstrated by..."
  • Followed by the main statement "Earle's impact has been unprecedented"
  • This is also a full sentence

• When we have two complete thoughts that each express their own main idea, we need to separate them into two sentences with a period.

So we need: conservation. As

The correct answer is Choice B.

This creates two clear sentences:

1. "Marine biologist Sylvia Earle has been a pioneering force in ocean conservation."
2. "As demonstrated by her record-breaking deep-sea dives and establishment of marine protected areas worldwide, Earle's impact on ocean conservation has been unprecedented in both scope and influence."

GRAMMAR CONCEPT APPLIED

Separating Two Complete Thoughts into Sentences

When you have two complete independent clauses (groups of words with their own subject and verb that express complete thoughts), they need to be separated into distinct sentences with a period:

Pattern:

• Complete thought #1: [Subject + Verb + complete idea].
• Complete thought #2: [Subject + Verb + complete idea].

Example from another context:

• Incorrect: "The scientist made a breakthrough discovery, her research changed the field forever"
  • Two complete thoughts improperly joined with just a comma (comma splice)

• Correct: "The scientist made a breakthrough discovery. Her research changed the field forever."
  • Two separate sentences, each expressing a complete thought

How this applies to our question:

• First complete thought: "Marine biologist Sylvia Earle has been a pioneering force in ocean conservation."
  • Subject: Sylvia Earle
  • Verb: has been
  • Complete idea about her being a pioneering force

• Second complete thought: "As demonstrated by her record-breaking deep-sea dives and establishment of marine protected areas worldwide, Earle's impact on ocean conservation has been unprecedented in both scope and influence."
  • Even though it starts with an introductory dependent clause ("As demonstrated..."), the main part is still a complete independent clause
  • Subject: Earle's impact
  • Verb: has been
  • Complete idea about her impact being unprecedented

These two complete thoughts need a period between them, creating two properly structured sentences.