Which phrase describes air pressure? A. decreases with denser air
B. decreases as altitude decreases
C. equals mass divided by volume
D. decreases as a result of fewer air particles pushing down

Which revelation resulted from the observation of the spectrum of different galaxies? a. there were more galaxies whose spectrum was blueshifted b. there were no galaxies whose spectrum was redshifted c. there were more galaxies whose spectrum was redshifted d. there were no galaxies whose spectrum was blueshifted