Definition - What does System Unit mean? A system unit is the part of a computer that houses the primary devices that perform operations and produce results for complex calculations. It includes the motherboard, CPU, RAM and other components, as well as the case in which these devices are housed. This unit performs the majority of the functions that a computer is required to do.
size constancy - the tendency to perceive the veridical size of a familiar object despite differences in their distance (and consequent differences in the size of the pattern projected on the retina of the eye)
Visual Form Constancy. Visual Form Constancy is the ability to mentally manipulate forms and visualize the resulting outcomes. This skill also helps children recognize an object in different contexts regardless of changes in size, shape, and orientation. Children with poor form-constancy may struggle to recognize objects when turned a different direction or viewed from a different vantage point. They can fail to recognize words they know that are presented in a different manner, i.e., written on paper, in a book, or on the board.