Marine biologist Sylvia Earle pioneered the use of submersibles for deep-sea research in the 1970s. The California Academy of Sciences...

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

• First sentence:
  • Marine biologist Sylvia Earle
    • pioneered the use of submersibles
      • for deep-sea research
      • in the 1970s.

• Second sentence:
  • The California Academy of Sciences
    • recently acquired archival footage
      • documenting one of [?] most dangerous solo dives
        • to a depth of 1,250 feet.

• Where [?] = what we need to decide between:
  • Earle / Earle's / Earles' / Earle's...'

Understanding the Meaning

Let's start with the first sentence to understand who and what we're talking about:

• 'Marine biologist Sylvia Earle pioneered the use of submersibles for deep-sea research in the 1970s.'
  • This introduces us to Sylvia Earle
  • She's a marine biologist who did pioneering work
  • Specifically, she was one of the first to use submersibles (underwater vehicles) for deep-sea research
  • This happened back in the 1970s

Now the second sentence:

• 'The California Academy of Sciences recently acquired archival footage'
  • A scientific institution got some old recorded footage

This footage was 'documenting one of _____ most dangerous solo dives to a depth of 1,250 feet.'

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

• We're deciding whether to write: Earle, Earle's, Earles', or Earle's...'
• The key difference is about showing possession (ownership)

To see what works here, let's understand what this phrase is telling us!

The footage documents 'one of _____ most dangerous solo dives'

• We're talking about solo dives
• Specifically, the most dangerous ones
• More specifically, one of the most dangerous ones
• But whose dives?

Now here's the key question: Whose dives are we talking about?

• These are the dives that belong to Earle
• The footage shows one of Earle's dives

What do we notice about the structure here?

• We need to show that these dives belong to Earle (one person)
• When something belongs to a singular person, we show that ownership by adding an apostrophe + s to their name
• So we need: Earle's most dangerous solo dives

The correct answer is Choice B: Earle's most dangerous

GRAMMAR CONCEPT APPLIED

Forming Possessives with Singular Nouns

When you need to show that something belongs to one person or thing, you add an apostrophe + s to that noun (called a possessive form in grammar terms):

Pattern: [Singular noun] + 's + [thing that belongs to them]

Examples:

• Sylvia Earle's dives = the dives that belong to Sylvia Earle
• The scientist's research = the research that belongs to the scientist
• Marcus's book = the book that belongs to Marcus

This is different from plural possessives:

• The Earles' house (if we're talking about the whole Earle family)
• The scientists' research (if we're talking about multiple scientists)

In our question:

• We're talking about dives that belong to one person: Sylvia Earle
• So we use the singular possessive: Earle's
• "One of Earle's most dangerous solo dives" = one of the dangerous dives that belong to Earle