Grammar Post- Pronouns

I made a mistake in my political cartoon analysis paper with a pronoun. It's a simple mistake that when your not paying close attention, like I was, you can make this easy error. My advice is to read it out loud and also to learn all the rule which there are about seven. To learn them all go HERE.
Definition. - A pronoun is a word that takes the place of a noun. Pronouns can be in one of three cases: Subject, Object, or Possessive.