Marcus is studying plant growth. He uses four identical trays of potting soil. He plants 2 marigolds in the first tray, 5 in the second tray, 8 in the third tray, and 15 in the last tray.
Marcus places each of the trays on the same table near a window. Each day he adds an
equal amount of water to the soil in each tray. Once a week for the next month, Marcus
measures the heights of the plants in each tray.