Final answer:
Perceptual and functional similarities that feed into overextension for a clock are functionality and shape.
Step-by-step explanation:
The perceptual and functional similarities that feed into overextension for a clock are functionality and shape. Overextension occurs when a child uses a word to describe a broader category than it actually represents. In the case of a clock, a child might use the word 'clock' to refer to any object that has a similar shape and serves a similar function, such as a round kitchen timer or a wristwatch.