That the species represented a transitional form between aquatic and terrestrial vertebrates was acknowledged by all ______ pinpointing its exact...

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

• That the species represented a transitional form
• between aquatic and terrestrial vertebrates
• was acknowledged by all paleontologists (?)
• pinpointing its exact evolutionary position
• remained subject to intense debate.

Understanding the Meaning

Let's start reading from the beginning:

'That the species represented a transitional form between aquatic and terrestrial vertebrates'

• This is telling us what scientists believed about this species -
  • that it was a transitional form
  • meaning something in between water-dwelling and land-dwelling vertebrates

'was acknowledged by all paleontologists'

• So everyone studying ancient life agreed on this point
• The complete first thought is:
  [This idea about the transitional form] was acknowledged by all paleontologists

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

• We're deciding what punctuation (if any) should come after 'paleontologists'
• Our options are: colon, semicolon, comma, or nothing

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

'pinpointing its exact evolutionary position remained subject to intense debate'

• 'Pinpointing its exact evolutionary position' = figuring out exactly where this species fits in the evolutionary timeline
• 'remained subject to intense debate' = was still being argued about

So now let's look at the complete picture:

• First part: Everyone agreed the species was transitional
• Second part: BUT exactly where it fit was still debated

What do we notice about the structure here?

• The first part - 'That the species...was acknowledged by all paleontologists' - is a complete thought that could stand alone as a sentence
  • It has a subject (the 'that' clause) and a verb (was acknowledged)
• The second part - 'pinpointing its exact evolutionary position remained subject to intense debate' - is also a complete thought that could stand alone
  • It has a subject (pinpointing...) and a verb (remained)
• So we have TWO complete sentences here, expressing related but contrasting ideas
  • They're connected in meaning (both about the same species)
  • But they need proper punctuation to join them

When you have two complete sentences that are closely related, you join them with a semicolon.

So we need: paleontologists;

The correct answer is B) paleontologists;

GRAMMAR CONCEPT APPLIED

Joining Two Complete Thoughts with a Semicolon

When you have two complete sentences (each with its own subject and verb, each able to stand alone) that are closely related in meaning, you can join them with a semicolon (called independent clauses in grammar terms):

Pattern:

• [Complete Thought 1]; [Complete Thought 2]

Example 1:

• The experiment yielded unexpected results; the research team decided to repeat the trial.
• First part: complete sentence (experiment yielded results)
• Second part: complete sentence (team decided to repeat)
• Semicolon joins them because they're closely related

Example 2:

• Marine biologists tagged the whale in 2020; they tracked its migration for three years.
• First part: complete sentence (biologists tagged the whale)
• Second part: complete sentence (they tracked its migration)
• Both can stand alone; semicolon shows the connection

In our question:

• [That the species represented a transitional form...was acknowledged by all paleontologists]; [pinpointing its exact evolutionary position remained subject to intense debate]
• First part: complete sentence
• Second part: complete sentence
• Semicolon properly joins these related but contrasting ideas

Key point: Both parts must be complete thoughts. If one part cannot stand alone as a sentence, you cannot use a semicolon.