The thinning of the troposphere away from the equator is primarily a result of land masses moving towards the poles. shifting of the continental plates due to plate tectonics. differences in solar energy striking the earth the number of clouds in the mesosphere and thermosphere

C) differences in solar energy striking the Earth

Ithink the answer is b

The us is first  the  u.s. economy  remains the  largest in the world  in terms of nominal  gdp. however, the  u.s. economy  loses its spot as the number one  economy  to china when  measured  in terms of  gdp  based on ppp. in these terms, china's  gdp  is $23.19 trillion exceeds the  u.s. gdp  of $19.42 trillion