Final answer:
A batwing and a cat paw are best described as homologous structures because they have similar development and bones due to a common ancestor.
Step-by-step explanation:
The term that best describes the relationship between a batwing and a cat paw is homologous structures. These structures have different functions but similar bones and development because they were inherited from a common ancestor, indicating that they share a common evolutionary past. Homologous structures are different from analogous structures, which are similar in function and appearance but do not share an origin in a common ancestor and evolved independently in different lineages, such as the wings of bats and insects. The wings of a bird and a bat are both homologous and analogous; they share a similar embryonic origin and perform the same function of flight, yet evolved from the same ancestral structures.