12. Fish fins and whale flippers are both used for swimming, but are not made the same structurally Does this represent homologous, vestiglal, or analogous structures?

## Step 1<br />The problem is asking us to identify the type of structure that fish fins and whale flippers represent. The options are homologous, vestigial, or analogous structures.<br /><br />## Step 2<br />Homologous structures are those that have a common ancestry, meaning they evolved from the same structure in a common ancestor. Vestigial structures are remnants of structures that had a function in an ancestral species but are no longer functional in the current species. Analogous structures are those that perform a similar function but do not share a common ancestry.<br /><br />## Step 3<br />Fish fins and whale flippers perform a similar function (swimming), but they do not share a common ancestry. Fish fins are a primitive feature that evolved in fish, while whale flippers are a modified version of the limbs of terrestrial mammals. Therefore, they are analogous structures.