* Fox and Dog: Foxes and dogs are both canids, meaning they belong to the same family (Canidae). They share a common ancestor, but they are distinct species that diverged millions of years ago.
* Fox and Rat: Foxes and rats are not closely related. Foxes are mammals in the order Carnivora, while rats are rodents in the order Rodentia. They have very different evolutionary histories and physical characteristics.
To summarize:
* Foxes and dogs are more closely related than foxes and rats.
* Foxes and rats are both mammals, but they belong to completely different orders, indicating a distant relationship.