A designed experiment is described. Identify the specified element of the experiment.

In a clinicaltrial, 780 participants suffering from high blood pressure were randomly assigned to one of three groups. Over a one-month period, the first group received a low dosage of an experimentaldrug, the second group received a high dosage of thedrug, and the third group received a placebo. The diastolic blood pressure of each participant was measured at the beginning and at the end of the period and the change in blood pressure was recorded. Identify the experimental units(subjects).