A scientist measures the heart rates of 30 students from the same class before and after they run for different amounts of time. The experimental set up is
shown below:
• Group 1 had ten students who ran one lap.
• Group 2 had ten students who did not run at all.
• Group 3 had ten students who ran two laps.
Group 4 had 30 students from another class whose heart rates were
not measured.
Which group is the control in this experiment?
A. Group 1 from this class
B. Group 2 from this class
C. Group 3 from this class
D. Group 4 from another class