The collection of endangered plant specimens at the botanical garden ______ crucial for biodiversity research and conservation efforts worldwide.

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 collection
  • of endangered plant specimens
  • at the botanical garden
• [?] (is/are/are providing/have been)
• crucial
  • for biodiversity research and conservation efforts worldwide.

Understanding the Meaning

Let's start reading from the beginning:

The sentence is about:

• 'The collection'
  • A specific collection we're talking about
• 'of endangered plant specimens'
  • This tells us what kind of collection - it contains endangered plant specimens
• 'at the botanical garden'
  • This tells us where this collection is located

Now here's where we need to fill in the blank:

• 'The collection ______ crucial'

Let's look at our choices:

• Option B gives us "is"
• Options A, C, and D give us "are," "have been," or "are providing"

The key question is: does our subject need a singular or plural verb?

What's our subject?

• 'The collection' is our subject
  • This is a singular noun
• 'of endangered plant specimens' and 'at the botanical garden'
  • These are phrases that describe the collection
  • The word 'specimens' is plural, but it's tucked inside a describing phrase
  • It's not the main subject of the sentence

So we need a singular verb to match 'collection': is matches our singular subject.

Now let's read the rest to see the complete picture:

• 'crucial for biodiversity research and conservation efforts worldwide'
  • This tells us why the collection matters
  • It's important for research and conservation work around the world

The complete meaning:

• This particular collection of endangered plant specimens at the botanical garden serves as something crucial - it's really important for biodiversity research and conservation efforts happening worldwide.

The correct answer is B.

Grammar Concept Applied

Matching Verbs to Subjects When Describing Phrases Get in the Way

The verb in a sentence must agree with the true subject, not with nouns that appear in describing phrases (called prepositional phrases in grammar terms) between the subject and verb.

The pattern to watch for:

• Subject (often singular): The collection
• Describing phrase with plural noun: of endangered plant specimens
• Verb must match the subject: is (not are)

Common trap:
It's tempting to match the verb to "specimens" because it's plural and sits right before the blank. But "specimens" is inside the phrase "of endangered plant specimens," which is just describing which collection we're talking about.

How to identify the true subject:

1. Find the main noun before any "of/at/in/with" phrases
2. Temporarily cross out or ignore the describing phrases
3. Check if subject and verb agree: "The collection... is crucial" ✓

More examples following this pattern:

• Singular subject with plural in describing phrase:
  • The box of chocolates is on the table
  • (Not "are" - "chocolates" is in the describing phrase)
• Plural subject with singular in describing phrase:
  • The members of the committee are voting today
  • (Not "is" - the true subject is "members," which is plural)

In our question: "The collection... is crucial" - the singular "collection" needs the singular verb "is," regardless of the plural "specimens" in the describing phrase.