Homologous organs are similar in which aspect?

Homologous organs are similar in origin, indicating that they share a common ancestry. This means that these structures arise from the same embryonic tissue and have evolved from a common ancestor, even if they serve different functions in the organisms that possess them. For example, the forelimbs of humans, bats, and whales are considered homologous because they are structurally similar and have evolved from a common ancestral limb, despite being adapted for different uses—grasping, flying, and swimming, respectively. This common origin highlights evolutionary relationships among species and helps to illustrate how different adaptations can arise from similar starting points.

In contrast, homologous organs are not necessarily similar in function, color, or size. Their differences in function demonstrate how natural selection can shape structures for specific roles rather than maintaining the same utility across different species. Therefore, while the appearance of these organs may vary greatly—sometimes in color or size—what unites them is their shared origin and evolutionary lineage.