When you crack the back of a minion and then shake, they will glow like a glow stick. Kevin was wondering if temperature has any effect on how brightly they can glow. To test this, he will place one glowing minion in a walk-in refrigerator, one in the living room, and one in a sauna. He will then observe the brightness of each glowing minion. What is the independent or manipulated variable?
A. temp
B. brightness
C. shaking time
D. cracking the back of the minion