Science Buddies: "Ask an Expert"

Good morning sir/ma'am,
I am writing a research paper about a maximum of 1500 words. I became interested in the Science Buddies lab, Why Do Some People Respond to Drugs Differently than Others, however, I am struggling to create a research question in which isn't broad. Any suggestions?
Thank you.

Dear tayala17,

One research question that I could think of is : How do gene mutations affect how people respond to a drug?

Good luck with your research paper!

RicaC