Mary wanted to determine which type of fertilizer would her plants grow taller. she got 16 plant pots andd scooped 2 cups of the same type of soil in each. then she planted 1 sunflower seed in each plant pot. the first four pots were placed in her garden to grow. no fertilizer was added to this group. mary did this to see how tall sunflower plants would grow under normal conditions. in the next four pots she added miracle grow. in the four pots she added grow rite and the last four pots she added perlite. she placed all the plant pots in the same are of the garden. how many trials were conducted?