A model is a three-dimensional of a person/thing or of a proposed structure.
A mock up is a model or replica of a machine or structure, used for instructional or experimental purposes.
A prototype is a first or preliminary version of a device or vehicle from which other forms are developed.
The correct answer is d. Computer sizes have decreased with each new model created.
Computer sizes have nothing to do with the internet. They've become smaller due to technological development, not because of internet.
