Ateam of scientists has devised a new chemical fertilizer that its members believe will increase crop yields. the team planted three garden plots with corn. the soil was similar in each, and equal amounts of water were applied to each plot. one plot was treated with a common commercial fertilizer, another was treated with the new fertilizer, and the third plot was not given any fertilizer. the experimenters measured yields as bushels of corn from each plot. the plot that did not receive fertilizer was the