The neuroplasticity observed in adult brains challenges earlier theories. Research shows that each region of the brain's hemispheres, despite being...

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 neuroplasticity observed in adult brains
• challenges earlier theories.
• Research shows that
• each region of the brain's hemispheres,
• despite being specialized for particular cognitive functions
• and connected through an intricate network of neural pathways,
• [?] capable of reorganizing itself
• in response to injury or new learning experiences.

Understanding the Meaning

The first sentence tells us:

• 'The neuroplasticity observed in adult brains challenges earlier theories.'
  • Neuroplasticity means the brain's ability to change and adapt
  • This ability in adult brains goes against what scientists used to think

Now the second sentence gives us more detail:

• 'Research shows that each region of the brain's hemispheres...'
  • We're talking about individual regions of the brain
  • 'Each region' means we're considering them one at a time

Then we get some descriptive information about these regions:

• 'despite being specialized for particular cognitive functions and connected through an intricate network of neural pathways'
  • Even though each region has its specific job
  • And even though they're all connected in complex ways

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

• The options are: are, is, have been, were
• They differ in whether they're singular or plural

To see what works here, let's read the rest of the sentence:

• '_____ capable of reorganizing itself in response to injury or new learning experiences.'
  • The region can reorganize - change its structure or function
  • This happens when there's an injury or when learning something new
  • Notice it says 'itself' - this confirms we're talking about something singular

What do we notice about the structure here?

• The subject is 'each region of the brain's hemispheres'
  • The core subject is 'each region'
  • 'Each' is always singular - it means one at a time
  • 'Of the brain's hemispheres' is just describing which region

• There's a long phrase in between:
  • 'despite being specialized... and connected...'
  • This describes the regions but doesn't change our subject
  • We can mentally set this aside when finding what the verb needs to agree with

• The verb must match 'each region' - which is singular

So we need is (Choice B). This gives us: 'each region... is capable of reorganizing itself.'

GRAMMAR CONCEPT APPLIED

Subject-Verb Agreement with "Each" and Interrupting Phrases

When "each" is the subject (or the main word in the subject), it always takes a singular verb - even when it's followed by "of" + a plural noun. The key is identifying the true subject and not being distracted by other words that come between the subject and verb.

Pattern with "each":

• Each of the students is ready (not "are")
• Each of the books has its own story (not "have")

Pattern with interrupting phrases:

• The main subject at the base level determines the verb
• Phrases that come between don't change the agreement
• Example: The manager, despite leading multiple teams, works from home
  • Subject: "The manager" (singular)
  • Interrupting phrase: "despite leading multiple teams"
  • Verb: "works" (singular)

In this question:

• Subject: "each region of the brain's hemispheres"
  • Core: "each region" (singular)
  • Describing phrase: "of the brain's hemispheres"
• Interrupting phrase: "despite being specialized... and connected..."
• Verb needed: "is" (singular to match "each region")
• Confirmation: "itself" later in the sentence confirms singular

The sentence structure tries to distract you with the plural word "hemispheres" and the long descriptive phrase, but the verb must agree with "each region" - singular.