Which 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?
Scientists know that Earth has been impacted by large asteroids in the past however; what happens if a major asteroid hits Earth now?
Scientists know that Earth has been impacted by large asteroids in the past, however what happens if a major asteroid hits Earth now?
Scientists know that Earth has been impacted by large asteroids in the past however what happens if a major asteroid hits Earth now?
The correct sentence is: "Scientists know that Earth has been impacted by large asteroids in the past; however, what happens if a major asteroid hits Earth now?"
The correct sentence is: "Scientists know that Earth has been impacted by large asteroids in the past; however, what happens if a major asteroid hits Earth now?"
The correct sentence is:
Scientists know that Earth has been impacted by large asteroids in the past; however, what happens if a major asteroid hits Earth now?
The semicolon (;) is used correctly to separate two independent clauses, and the comma (,) is used correctly to set off the transitional word "however" from the rest of the sentence.