Question 50·Medium·Boundaries
A study conducted by marine biologists revealed that the blue-ringed octopus produces a potent neurotoxin, tetrodotoxin _____ which can paralyze prey almost instantly.
Which choice completes the text so that it conforms to the conventions of Standard English?
For Standard English Conventions questions about punctuation and boundaries, first strip the sentence down to its core to see the main subject and verb, then identify which parts are extra (nonessential) information. Nonessential appositives (like names or abbreviations added to a noun) and nonessential clauses (often starting with "which") must be set off by commas or, for abbreviations, sometimes parentheses plus commas. Check each answer by reading the sentence aloud in your head: it should flow naturally, and every nonessential piece should be clearly separated without creating run-ons or awkwardly jammed-together phrases.
Hints
Identify the role of "which"
Look at the phrase starting with "which can paralyze prey almost instantly." Is this essential to identifying what the neurotoxin is, or is it extra information about it?
Think about commas with "which"
When you have a nonessential clause that starts with "which," what punctuation is usually placed right before "which"?
Consider how abbreviations are introduced
When a long scientific name is followed by its abbreviation, how is that abbreviation usually formatted in formal writing?
Combine both punctuation needs
You must both introduce the abbreviation correctly and punctuate the clause that begins with "which." Which option gives you the abbreviation in the typical format and also leaves a comma before "which"?
Step-by-step Explanation
Understand what information is being added
Read the sentence without the blank:
"A study conducted by marine biologists revealed that the blue-ringed octopus produces a potent neurotoxin, tetrodotoxin _____ which can paralyze prey almost instantly."
The phrase "tetrodotoxin" names the neurotoxin. The word that goes in the blank will add its abbreviation, and then the sentence continues with the clause starting with "which." That "which" clause gives extra (nonessential) information about the neurotoxin.
Recognize the nonessential clause starting with "which"
The phrase "which can paralyze prey almost instantly" is a nonessential relative clause. It gives extra information but is not necessary to identify the neurotoxin.
Nonessential clauses that start with "which" must be set off by a comma. That means there must be a comma right before "which." Whatever we put in the blank must leave a comma immediately before "which."
Decide how to show the abbreviation correctly
In scientific writing, an abbreviation for a long name is usually placed in parentheses right after the full term, like this pattern: "tetrodotoxin (TTX)."
Here, the full name "tetrodotoxin" is already there, so the blank should:
- Put TTX in parentheses to show it is an abbreviation of "tetrodotoxin."
- Include a comma after the parenthetical abbreviation so that the nonessential "which" clause is correctly set off by a comma.
Match the correct punctuation pattern to an answer choice
We need an option that:
- Puts TTX in parentheses directly after "tetrodotoxin," and
- Ends with a comma so that the sentence reads "tetrodotoxin (TTX), which can paralyze..."
Only choice D) (TTX), produces the correct and properly punctuated sentence:
"A study conducted by marine biologists revealed that the blue-ringed octopus produces a potent neurotoxin, tetrodotoxin (TTX), which can paralyze prey almost instantly."