Which sentence is punctuated correctly?
1. Scientists know that Earth has been impacted by large asteroids in the past however; what happens if a major asteroid hits Earth now?
2. Scientists know that Earth has been impacted by large asteroids in the past, however what happens if a major asteroid hits Earth now?
3. Scientists know that Earth has been impacted by large asteroids in the past however what happens if a major asteroid hits Earth now?
4. Scientists know that Earth has been impacted by large asteroids in the past; however, what happens if a major asteroid hits Earth now?
The fourth sentence is punctuated correctly: "Scientists know that Earth has been impacted by large asteroids in the past; however, what happens if a major asteroid hits Earth now?"
The sentence that is punctuated correctly is:
4. Scientists know that Earth has been impacted by large asteroids in the past; however, what happens if a major asteroid hits Earth now?
The sentence that is punctuated correctly is:
4. Scientists know that Earth has been impacted by large asteroids in the past; however, what happens if a major asteroid hits Earth now?
To determine the correct punctuation, we need to understand the function of the conjunction "however" and the use of commas. In this case, "however" is used to provide contrast or introduce a contrasting statement. When "however" is used in the middle of a sentence, it is typically set off by commas on both sides.
In sentence 4, the first comma is used to separate the main clause ("Scientists know that Earth has been impacted by large asteroids in the past") from the contrasting statement introduced by "however" ("what happens if a major asteroid hits Earth now?"). The second commas is used to set off the word "however" itself.
The other options either have missing or misplaced commas. In option 1, there is a comma before "however" but there should be no comma after it. In option 2, there are no commas used to set off "however" or the contrasting statement. In option 3, there is no comma used before or after "however".