1.1. Figure 1 shows the stroke volume at different heart rates of a person who has trained for a marathon and of a person who has not trained for a marathon.

Figure 1

(i) Compare the effect of heart rate on stroke volume of the person who has trained for a marathon with the person who has not trained for a marathon.

(2)

(ii) Calculate the cardiac output for the person who has trained for a marathon when the heart rate is 160 beats per minute.
Give the units in your answer.

(3)

1.2. Blood from the body enters the heart through the vena cava.

Describe how this blood flows through the heart and lungs to leave the heart through the aorta. Include references to the chambers of the heart and the relevant valves in your answer.