Earth satellites such as the International Space Station orbit at altitudes that are mainly above Earth's atmosphere. A simple and accurate way to comprehend the orbit of these satellites is to view them as
a. balanced between gravitational and centripetal forces.
b. beyond the main pull of Earth's gravity.
c. in mechanical equilibrium with a net force of zero.
d. having sufficient tangential velocities to fall around rather than into Earth.
e. All of the above.