Teaching multiple subjects in high school

Hello! I’ve been interested in becoming a high school teacher for quite sometime. I’ve always wanted to be an art teacher (also considering biology). I talked to someone I know who is a psychology professor at a college and he told me that my best route would be to get my masters in biology, due to higher job demand, and added that I would be able to teach both subjects. Naturally I’ve always had a passion for art and for biology and I would love to be able to do the both of them. I’m not really sure if he was correct about this, I’ve tried to look online and everything I found was pretty confusing. Does anybody know if this is actually possible? Thank you!