As a train rushes away from a crossing, the pitch of its horn goes down because . a sound waves get farther apart as the source of the sound moves closer
b sound waves get farther apart as the source of the sound moves away
c sound waves get closer together as the source of the sound moves away
d sound waves stay the same distance from each other as the source of the sound moves away

The awnser is b

Explanation:

The sound waves get smaller as the sound moves farther away, and since the sound waves are smaller, the sound is quieter. This is known as the Doppler effect.

alfred von schlieffen, german army chief of staff, was given instructions to devise a strategy that would be able to counter a joint attack. in december, 1905, he began circulating what later became known as the schlieffen plan. schlieffen argued that if war took place it was vital that france was speedily defeated.

3 hours because it is a decent distance.