Are there situations where a company may discriminate against an employee? What is reasonable accommodation and when does it apply?

Are there situations where a company may discriminate against an employee? What is reasonable accommodation and when does it apply? Can a company refuse to hire someone: a) with a visible tattoo? b) Someone who is transgender? c) A white person to work in a Chinese restaurant? d) A black actress to play the role of Amelia Earhart? Do you agree with the laws regarding discrimination?