who , whom, whose, which and that are relative pronouns that are used at the beginning of an adjective clause
Who and whom are used mainly for people and they can also be used for animals that are mentioned by name .
ex:The vacuum scared our cat Scooter, who was sleeping on the rug.
This is the teacher who teaches us English.
The witnesses whom I interviewed gave conflicting evidence
Whose is a possessive pronoun that can be used for people, animals or things
ex:
The man whose jacket is blue is my father.
Whose car ?
Which and that are used for animals in general or things.
EX:
The car that Jason bought runs on electricity and gas.
Bridget visited the park with her dog, which likes to chase squirrels.