Some questions must be answered with a cross in a box . If you change your mind about an
answer, put a line through the box and then mark your new answer with a cross .
Asthma occurs when the airways in the lungs become narrowed, which makes
breathing difficult.
It is thought that the caffeine contained in coffee might help people with asthma by
increasing their breathing rate.
The traces below show the breathing rate of a resting person before and after
drinking coffee.
Place a cross in the box next to the apparatus used to obtain these traces.
A a peak flow meter
B an ECG
C a respirometer
D a spirometer