Which sentence is punctuated correctly? (1 point)

Question

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?

Answer 1

The sentence that is punctuated correctly is:

"Scientists know that Earth has been impacted by large asteroids in the past; however, what happens if a major asteroid hits Earth now?"