The integration—of drought-resistant crops, efficient irrigation systems, and soil conservation methods— _____ sustainable agriculture as achievable e...

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 integration—of drought-resistant crops, efficient irrigation systems, and soil conservation methods—[?] sustainable agriculture as achievable even in arid regions;

this success has encouraged policymakers to invest in similar agricultural innovations worldwide.

Understanding the Meaning

Let's start reading from the beginning: 'The integration—of drought-resistant crops, efficient irrigation systems, and soil conservation methods—'

• This is talking about combining or bringing together three agricultural practices:
  • drought-resistant crops (plants that can survive with less water)
  • efficient irrigation systems (better ways to water crops)
  • soil conservation methods (ways to protect and preserve soil)
• The dashes here set off extra information telling us what's being integrated.

Now here's where we need to fill in the blank: 'The integration _____ sustainable agriculture as achievable even in arid regions'

Let's look at our choices:

1. having demonstrated
2. demonstrating
3. has demonstrated
4. have demonstrated

What do we need here? Let's think about the structure:

• 'The integration' is our subject - it's what this part of the sentence is about.
• The subject needs a main verb - what does the integration DO?
• Looking at the choices, A and B are verb forms that can't act as main verbs on their own (they're describing forms, not action forms).
• C and D are both main verb forms, but which one?

'The integration' is singular (one integration), so we need:

• has demonstrated (singular) - not "have demonstrated" (plural)

So the correct answer is C. has demonstrated.

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

The sentence continues after a semicolon: 'this success has encouraged policymakers to invest in similar agricultural innovations worldwide.'

• The semicolon connects two related complete thoughts
• 'This success' refers back to what was just described - the integration demonstrating that sustainable agriculture works
• This success has inspired policymakers worldwide to invest in similar innovations

The complete meaning:

• Combining these three agricultural methods has shown that sustainable agriculture can work even in very dry regions
• This proof of success has motivated policymakers around the world to fund similar innovations

GRAMMAR CONCEPT APPLIED

Subject-Verb Agreement with Singular Subjects

When a sentence has a singular subject, the verb must also be singular, even when there's extra descriptive information between the subject and verb.

The pattern:

• Subject: The integration (singular)
• Intervening phrase: —of drought-resistant crops, efficient irrigation systems, and soil conservation methods—
• Verb needed: has (singular) demonstrated

Key principle:

Even though there are multiple things listed in the phrase between the dashes (crops, systems, methods), these are describing what's being integrated. The subject itself is still "The integration" (one integration), so the verb must be singular.

Also important:

The sentence needs a main verb - a complete verb form that can stand on its own. Participles like "having demonstrated" or "demonstrating" cannot serve as the main verb of a sentence; they function as describing words. Main verbs in present perfect form (has/have + past participle) create complete sentences.

In this question:

"The integration" (singular subject) needs "has demonstrated" (singular main verb), not:

• "have demonstrated" (plural - doesn't agree)
• "having demonstrated" or "demonstrating" (participles - can't be main verbs)