A punctuation question with a joining word near the blank tests how two parts connect. Split at the blank, then find who or what each side is about and what it does. Ask, can each side stand alone? A comma with a joining word connects full sentences, a semicolon joins them without that word, and a colon or dash introduces an explanation or added detail. Use the sentence's structure and meaning, not the pause you hear.
Hints
- Hint 1
In the first part, look for who identifies the fern and the words that tell what that person did.
- Hint 2
Read the words after and, and find who or what is doing something there. Check whether that part can stand alone without the words before the blank.
Step-by-step
Test both sides of the join
Step 1Find the first complete thought
Read through soil, the word every choice supplies, to test where the first full sentence ends. Who does what? botanist Priya Desai identified a fern species tells us that Desai identified something, and the remaining words describe the fern's ability to absorb arsenic. Once soil completes that description, the first part can stand alone, so the punctuation will follow a complete thought.
- Step 2
Check what follows and
Does and introduce another thing Desai did, or a full sentence with someone or something else doing something? After it, the discovery has since inspired new methods names the discovery and says what it has done. The discovery is the subject, the thing this part is about, and the words that follow tell us it has inspired methods for cleaning up contaminated sites. So the second part is a full sentence of its own, not a phrase sharing Desai as its subject.
- Step 3
Use the join that works with and
What mark works with the and already in and the discovery? When and joins two full sentences, a comma belongs before it. The semicolon normally joins full sentences without and, while the colon and dash would introduce an explanation or set apart an added thought. The version with the comma links what Desai found and what the discovery later inspired. Choice B.