Answer:
1. Bats and cats: <em>Homology</em>
2. Whales and sharks: <em>Analogy</em>
Explanation:
In Biology, homology refers to <u>the similarity of features from different species of organisms that share a common ancestor</u>. This is the opposite of analogy, which refers to <u>a feature that has a similar function but is not derived from a common ancestor</u>.
In this case, bats and cats have forelimbs adapted for locomotion. This is a case of homologous characters because they both are descendants of tetrapods - four-limbed animals. Therefore, even though cats and bats look completely different, they both share a similar feature: forelimbs, a characteristic feature from their common early mammalian ancestors.
On the other hand, whales (mammals) and sharks (fish) do not share a common ancestor. So, the fins are analogous structures: both have a similar function because both have adapted to an aquatic environment but they have completely separate evolutionary origins.