(a)   monitors can be easily and safely wall mounted.

(a)   plotter have the paper lying flat under the pens.

(a)   plotter lies the paper on a drum that spins to drive the paper under the pen while the pen itself move across.

To enable you to hear sounds or music your system would need to have (a)   .

(a)   devices are used to change some physical value in response to a command from a computer.

Sensors and control devices togather with the controlling computer make up a control (a)   .

(a)   can be used by computer system to control elements of many household devices from washing machine, DVD Player or air conditioners.