Question: A student investigated the effect of the color of light on the growth of plants. Red, yellow, and green lights were used in the experiment. If another student were to conduct the same experiment, which would be the most important procedure to follow to yield the same results?

  Options: 
 A. to do the investigation at the same time of year
 B. to use the same chart for recording growth
 C. to do the investigation in the same room
 D. to use the same colors of lights
Answer: D