A topographic map shows two locations, X and Y, 0.5 miles apart. From the contour lines, the elevation of X is 800 feet and Y is 750 feet. What is the gradient between the
two locations?

What is the mercury length of time for one revolution around the sun?

How long does it take for saturn to orbit the sun?

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