Plants are able to support themselves in an upright position due to turgor pressure. Water maintains the turgor pressure in stems like air inflates a balloon. Which of the following body systems helps humans to support themselves?

Ascience research group is testing a new type of plant food. one trial is conducted in a controlled experiment. the data from the trial show that the plant that received the new food grew faster than the control plant. the group announces that the new plant food makes plants grow faster. what is the main weakness in this scientific claim?