Quinn enjoys watching the trains go by after school. He walks to a field that is between his school and house and sits on a large rock to wait for the train.

As the train approaches him, the sound waves are _____ which causes the pitch to be _____

blank 1
a. amplified
b. louder
c. compressed
d. spread out

blank 2
a. compressed
b. higher
c. lower
d. quieter