A student conducted an experiment with two rose plants to determine if a liquid formula for fertilizer produced greater growth than a dry formula. After testing each fertilizer on two different plants for one month, his data led to the conclusion that the liquid formula was a better promoter of plant growth. When he described his conclusion to his teacher, she told him he needed to conduct additional trials. The teacher most likely asked for additional trials because she did not believe the new formula helped plants grow better than the old formula. it was necessary to see data from more plants before the conclusion could be accepted. it was necessary to have tested the fertilizer on different kinds of plants. she thought he should test additional fertilizer formulas on the same two plants.