The geologic-time unit corresponding to the time that a system was deposited is the?

Scientists think that convection currents flow in earth’s a. continents. b. mantle. c. lithosphere. d. inner core.

Can someone answer all these questions i need it done by tonight. once again

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