A punctuation question about a name tests whether the name tells you which person or thing is meant. Look for clues about how many people or things are discussed, then ask do the words before the name identify one? A needed name takes no commas or dashes; an extra name inside a sentence needs paired commas or dashes. Then find the subject and its verb: a comma or dash can't separate them unless it closes an extra phrase.
Hints
- Hint 1
Look at the first sentence for how many bacteria the researchers identified.
- Hint 2
Mentally cross out the scientific name. Do the words before it still tell you which bacterium is meant?
- Hint 3
Find the verb after the blank, then ask what could help reduce plastic waste. Where does that whole subject end?
Step-by-step
Decide whether the name is needed
Step 1Find the clue about how many
The researchers identified several new bacteria, so the passage hasn't singled out one bacterium yet. Which one could help in polar regions? The choices change the punctuation around a scientific name. We need to tell whether that name says which bacterium is meant or adds a fact about one already identified.
- Step 2
Test whether the name says which one
Does The bacterium already identify one of the several new bacteria? It doesn't, because the alone can't tell us which member of the group is meant. Crossing out the name would leave a complete sentence about a bacterium helping reduce waste, but we'd lose which bacterium it means. The name is essential: it says which one, so it takes no commas. The version with commas around the name treats it as extra and can be set aside.
- Step 3
Locate the subject and its verb
Read on to could help, the verb that tells us what the bacterium might do. What could help reduce the waste? The subject, the words naming what could help, includes both The bacterium and the scientific name. A single mark can't separate that subject from its verb.
- Step 4
Test the mark before the verb
Check the versions that put a mark directly before could help. The version with only a comma after the name separates the subject from its verb, and the version with a dash does the same. The version with no punctuation lets the whole subject lead straight into its verb. Choice B.