Evans wants to determine the effect of color on the temperature of the air inside of different colored boxes. He places white, black, and red boxes of the same size and material in the sunlight and a thermometer is placed inside each box. He observes and records the temperatures in the boxes at specific times throughout the day. What is the test variable independent variable in this
investigation?
A. repealed trials
B. size of the boxes
C. color of the boxes
D. recorded temperatures