Polyphenols are organic compounds _________ among their many roles, provide pigment that helps protect plants against ultraviolet radiation from sunli...

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

• Polyphenols are organic compounds
• that [?]
  • among their many roles,
  • provide pigment
    • that helps protect plants
      • against ultraviolet radiation
        • from sunlight.

Understanding the Meaning

The sentence starts by telling us what polyphenols are:

• 'Polyphenols are organic compounds'

Then it continues describing these compounds:

• 'that... among their many roles, provide pigment that helps protect plants against ultraviolet radiation from sunlight.'

This is where we have the blank – right after the word "that."

Let's look at the choices:

• We're deciding what punctuation (if any) should come after "that"
  • A dash, semicolon, comma, or colon

To see what works here, let's read the rest and understand what the sentence is telling us!

The sentence continues: 'among their many roles, provide pigment that helps protect plants against ultraviolet radiation from sunlight.'

Now let's understand what this is telling us:

• 'provide pigment that helps protect plants...'
  • This is the main action being described – these compounds provide pigment
  • This pigment has a protective function for plants

• 'among their many roles'
  • This phrase adds context – it's acknowledging that providing pigment is just one of the things polyphenols do
  • Notice there's already a comma after "roles"

What do we notice about the structure here?

• The word "that" after "compounds" is connecting the description to what it describes
  • "compounds that... provide pigment"

• The phrase "among their many roles" is interrupting the natural flow
  • It's inserted between "that" and "provide"
  • Without this phrase, it would read: "compounds that provide pigment"

• When you insert an interrupting phrase in the middle of a sentence, you need to set it off with matching punctuation on both sides
  • There's already a comma after "roles"
  • So we need a comma after "that" to open this interrupting phrase

The correct answer is Choice C (that,) – this creates the pair of commas that properly sets off the interrupting phrase: "that, among their many roles, provide..."

GRAMMAR CONCEPT APPLIED

Using Commas to Set Off Interrupting Phrases

When you insert additional information into the middle of a sentence – information that adds context but interrupts the main flow – you need to set it off with matching punctuation marks on both sides. The most common way to do this is with a pair of commas (though you can also use dashes or parentheses, called parenthetical elements in grammar terms).

The Pattern:

• Main flow: The report revealed significant findings
• With interrupting phrase: The report, according to experts, revealed significant findings
  • Opening comma after "report"
  • Closing comma after "experts"
  • The phrase "according to experts" is set off from the main flow

Another example:

• Main flow: Students who study regularly perform better
• With interrupting phrase: Students who, despite busy schedules, study regularly perform better
  • Opening comma after "who"
  • Closing comma after "schedules"
  • "despite busy schedules" interrupts but needs both commas

In our question:

• Main flow: compounds that provide pigment
• With interrupting phrase: compounds that, among their many roles, provide pigment
  • Opening comma after "that"
  • Closing comma after "roles" (already provided)
  • "among their many roles" interrupts the relative clause