Final answer:
The perpetual and functional similarities that can lead to overextension for a clock are known as analogous features, which arise from different species independently developing similar traits due to similar environmental pressures.
Step-by-step explanation:
When discussing the perpetual and functional similarities that lead to overextension for a clock, the term we are referring to is analogous features. These are traits that originate not from a common evolutionary path, but from separate species responding to similar environmental pressures, which results in similar structures or functions. An example of analogous structures is the body shapes of dolphins and fish, which are similar because of convergent evolution in response to moving through water efficiently, despite dolphins being mammals and fish being part of a different class of vertebrates.
Homologous structures, on the other hand, have a similar embryonic origin and reflect an evolutionary path from a common ancestor. An example of homologous structures is the bones in the wings of bats and the bones in bird wings, which, despite serving the same function of flight, originate from common ancestral traits. Thus, the correct answer to the question is A) Analogous features.