Emily is studying how a person's breathing rate is affected by aerobic and anaerobic exercise. To do this, she measures the breathing rate of her test subject while the subject engages in 10 minutes of aerobic exercise. She then measures the breathing rate of her test subject while the subject engages in 10 minutes of anaerobic exercise. Which of the following graphs would be best for Emily to use to display the data she collects?
A.
a double line graph
B.
a bar graph
C.
a single line graph
D.
a circle graph