The solar
system formed when gravity began collapsing
a cloud of gas, rock, ice, and other materials.
Where did the gravity come from to initiate
this collapse? Explain.

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.

Which of the following types of nonrenewable fuel sources requires the storage of radioactive waste? a. coal b. nuclear c. solar d. oil

Countries that have a traditional economy often develop at a slower pace than countries with a free market economy. true or false