The sound is reflected more in space. The pressure is too high inside the spaceships. The spaceships are traveling faster than sound. There is no air in space for the sound to travel through.
I gave my students this multiple choice question: The crews of two boats at sea can communicate with each other by shouting. Why is it impossible for the crews of two spaceships a similar distance apart in space to do this?

Only one answer is correct among these 4 choices:
- The sound is reflected more in space.
- The pressure is too high inside the spaceships.
- The spaceships are traveling faster than sound.
- There is no air in space for the sound to travel through.

Could you tell me which one is correct?

There is no air in space for the sound to travel through.