Eddie is performing an experiment. He asked the question what type of soil makes plants grow the fastest. He has four plants. He
gives Plant #1 with potting soil,Plant #2 with sand, Plant #3 with dirt from his yard, and Plant #4 with gravel. All of the plants are kept on the same shelf next to the window and receive the same amount of water. After 4 months, Plant #1 is 100 cm tall, Plant #2 & #3 are 115 cm tall, and Plant #4 is 12 cm tall. What is the Manipulated Variable in this Experiment?
