Can we use stepper motors for controlling throttle position in automotive applications?

Can we use servo motors?

What are the advantages and disadvantages?

What are actuators generally mean?
Can a stepper motor be called as an actuator?

 

An actuator is any device that converts some source of energy (electricity, compressed air, stored energy in a spring) into mechanical motion. Therefore a stepper motor is just one form of actuators in general.

From a user perspective, stepper motors and servo motors are basically the same thing. Stepper motors are used in lots of printers, to place the print head in the right column before anything is done to the paper. The hard part is matching up a motor to a force that you wish to apply. These motors can hold something in any specified position for as long as you like. The rest is mechanics and lever arms and such.