Final answer:
The term 'exactly analogous' means two or more items are comparable due to their similar functions or concepts, not shared origins. In biology, analogous structures serve similar functions but evolved independently, while homologous structures share a common evolutionary origin but may serve different functions.
Step-by-step explanation:
The term exactly analogous refers to two or more items that are comparable because they perform the same function or present a similar concept, though they do not necessarily have a common origin. In biology, analogous structures are those which evolved independently to serve similar functions in different organis
ms. This is unlike homologous structures, which have a common evolutionary origin but may serve different functions.
An example of analogous structures is the wings of bats and birds. While both serve the purpose of flight, their similarity is a result of convergent evolution rather than a shared ancestry.
This distinction is the basic difference in what homologous and analogous imply in a biological context.
According to the options provided, the correct answer to the basic difference between homologous and analogous structures is that things that are analogous result from convergence and things that are homologous result from common ancestry.