The grinding and shaping of rock surfaces by the sandblasting action of particles carried by wind is

The graph below plots the temperature and luminosity of stars on the main sequence.

Which outcome is not caused by gravitational forcea. gas and dust come together to form a planet b. planets orbit a star c. two atoms come together to form a molecule d. stars cluster to form a galaxy

Many countries in africa have had difficulty creating democratic governments following their independence. all of the following issues have most likely contributed to this problem, except