Mark notices he has dropped calls on his cell phone when he walks into his bedroom. his friend told him to try and were wrap aluminum foil around his phone to get better signal mark talks on the phone 3 times while walking into his bedroom and drops 2 of the 3 cause he wraps his phone and in aluminum foil on talks on the phone 3 more times while walking into his bedroom with a newmanham foil on his fawn he only drops one call. what's the independent variable what's the dependent variable and what's the control variable