Passage III
Cloud cover is the percent of Earth's surface covered by clouds. Cloud cover may increase because of an increase in the cosmic ray flux (number of high-energy particles from space reaching Earth per m2 per hour). Table 1 shows how Earth's cover of low clouds (0 km to 3.2 km altitude) varies with the cosmic ray flux. Figures 1−3 show the relative cosmic ray flux, RCRF (the percent below the flux measured on October 1, 1965), and the monthly average cover of high clouds (6.0 km to 16.0 km altitude), middle clouds (3.2 km to 6.0 km altitude), and low clouds, respectively, from January 1980 to January 1995.
13. The percent of Earth's surface covered by high clouds in January 1987 was closest to which of the following?
Your Answer is
Correct Answer is B
Explanation
Look at figure 1, corresponding to the dotted line of monthly average cover of cloud, when the abscissa is 1987, the ordinate is about 13.5