1.convection current is caused by differences in a) temperature.
b) mass.
c) air pressure.
d) color

Witch layer of the atmosphere has the most air pressure

Which volcanic eruption caused the most deaths

Which evidence is most likely used to indicate the beginning of solar system formation? a. materials combined to form a mass. b. materials were pulled together by gravity. c. water condensed and collected to form oceans. d. different species of microorganisms lived on earth.