A punctuation question with an added description tests whether you can see where the main sentence pauses and continues. Find the subject and follow its verbs, especially when the sentence continues with and. Then cross out the added description to see whether the sentence still works. An insert, extra information the sentence can do without, needs matching commas, dashes, or parentheses at both ends when it's in the middle. Track the whole insert, since punctuation inside it may belong to smaller pieces.
Hints
- Hint 1
Look for the axolotl’s verbs on both sides of the blank. How are they joined?
- Hint 2
Cross out the added description and read the main sentence through to and uses. Does it still say what the axolotl does?
- Hint 3
Which punctuation belongs inside the added description? Once you've found the whole description, check the marks at its two ends.
Step-by-step
Cross out the description and match its marks
Step 1Find the axolotl’s two verbs
Start with the axolotl retains its larval form, which gives us the subject and the first verb in the main sentence. What does and uses this unusual physiology connect to? It gives the axolotl a second verb, so the sentence describes two things the same animal does. We're choosing punctuation between those verbs, and the axolotl’s main sentence continues after the blank.
- Step 2
Test the whole added description
Does the description add another thing the axolotl does? It names the process, so cross out the description but keep adulthood to complete retains its larval form throughout. What's left is a full sentence: the axolotl retains its larval form throughout adulthood and uses this unusual physiology to regenerate entire limbs. The insert, extra information the sentence can do without, ends after known as neoteny, right before and uses. The comma after process sits inside the description, so it doesn't close the whole insert.
- Step 3
Match the marks at both ends
In the middle of a sentence, an insert needs matching marks at its beginning and end. The version with no mark after neoteny leaves the insert open, and the version with a semicolon breaks off a phrase that can't stand alone. A colon also can't match a closing dash. Paired dashes set off the full description without cutting off and uses, so use adulthood—an unusual biological process, known as neoteny—. Choice A.