Hi! 1. Who are / who is depends on what follows: Who am I Who are you Who is he Who is she Who is it Who are we Who are you Who are they 2. You should say 'If you're interested in...' Hope that helps!

1) It depends, Who are you? Who is she? 2) It depends. For example If you have interest in playing football, you can join our team.

1) It is correct to say "Who are" and "Who is". It depends on a subject. For instance, Who are you to judge me? Who is the girl talking to Pablo? 2) your sentence is correct