Why are satellites placed into orbit at least 150 km above earth’s surface?

to avoid air resistance
to match earth’s curvature
to create inertia
to increase friction

The correct answer is to avoid air resistance

Satellites are moving in the orbit because of the initial force that was applied through the rockets. Now for the satellites to remain in orbit there should not be any friction. As air resistance is also friction that is provided by air, the satellites are 150KM above the surface to avoid air resistance