(a)[3]
State three features that enable alveoli to work effectively as a gas exchange surface.
(b(i))[1]
Identify which letters in Fig. 2.1 label the muscles that contract during inspiration.
(b(ii))[1]
State the function of cartilage in the breathing system.
(c(i))[2]
State the balanced equation for aerobic respiration.
(c(ii))[3]
Explain the mechanism that links the increase in physical activity to the changes in breathing.