What happened to the speed of light if it travels from air into glass?

Ineed the answers for these promblems i have

What is the force that opposes motion and works against the downward pull? a) friction b) gravity c) weight d) acceleration

Which statement best describes the direction of the buoyant force on any object? a. opposite the force of gravity b. in the same direction as the weight c. in the direction of motion of the object d. opposite the direction of motion of the object