Science Buddies: "Ask an Expert"

OK I'm taking ninth grade Earth and Space science and I forgot what the three types of variables are for this project.
I took peoples heart rates while they listened to diffrent genres of music.

WHAT WOULD THEY BE?

Since you said in your subject line, you would only be there an hour, we haven't answered.

Don't hesitate to post again!

Ceal Craig
(Ask an Expert On Duty)