Dr. Elena Vasquez spent fifteen years studying the symbiotic relationship between mycorrhizal fungi and tree roots in tropical ______ her...

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

• Dr. Elena Vasquez
  • spent fifteen years
    • studying the symbiotic relationship
      • between mycorrhizal fungi and tree roots
        • in tropical rainforests[?]
• her research
  • has revolutionized our understanding
    • of forest ecosystems and their interdependence.

Understanding the Meaning

Let's start reading from the beginning:

'Dr. Elena Vasquez spent fifteen years studying the symbiotic relationship between mycorrhizal fungi and tree roots in tropical rainforests'

This tells us:

• Dr. Vasquez dedicated 15 years to research
• She was studying how fungi and tree roots work together
  • "Symbiotic relationship" means they help each other
• This was specifically in tropical rainforests

This is where we have the blank: after "rainforests."

Let's look at the choices:

• A: no punctuation
• B: comma only
• C: comma + and
• D: and only

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

'her research has revolutionized our understanding of forest ecosystems and their interdependence'

This tells us:

• Her research changed everything we thought we knew
• Specifically about how forest ecosystems work together

What do we notice about the structure here?

• The first part is a complete thought:
  • "Dr. Elena Vasquez spent fifteen years studying the symbiotic relationship between mycorrhizal fungi and tree roots in tropical rainforests"
  • It has a subject (Dr. Vasquez), a verb (spent), and expresses a complete idea
• The second part is ALSO a complete thought:
  • "her research has revolutionized our understanding of forest ecosystems and their interdependence"
  • It has a subject (her research), a verb (has revolutionized), and expresses a complete idea
• We have two complete thoughts that need to be properly connected

When you connect two complete thoughts, you can't just run them together or use only a comma. You need proper punctuation:

• Either: comma + a connecting word (like "and")
• Or: a semicolon
• Or: a period (making them separate sentences)

So we need comma + and to properly connect these two complete thoughts.

The correct answer is C: rainforests, and

GRAMMAR CONCEPT APPLIED

Connecting Two Complete Thoughts

When you have two complete thoughts (called independent clauses in grammar terms), you must connect them properly. Each complete thought has its own subject and verb and could stand alone as a sentence.

Three ways to connect them correctly:

1. Comma + connecting word (and, but, or, so, yet, for, nor)
   • First complete thought, and second complete thought
   • Example: "Dr. Vasquez studied fungi for years, and her research revolutionized the field"
2. Semicolon
   • First complete thought; second complete thought
   • Example: "Dr. Vasquez studied fungi for years; her research revolutionized the field"
3. Period (separate sentences)
   • First complete thought. Second complete thought
   • Example: "Dr. Vasquez studied fungi for years. Her research revolutionized the field"

What you CANNOT do:

Run them together with no punctuation (run-on sentence)

• "Dr. Vasquez studied fungi for years her research revolutionized the field"

Separate them with only a comma (comma splice)

• "Dr. Vasquez studied fungi for years, her research revolutionized the field"

Use connecting word without comma

• "Dr. Vasquez studied fungi for years and her research revolutionized the field"

In our question: We have two complete thoughts about Dr. Vasquez's work. The correct way to connect them is with comma + and.