(a(i))[4]
Fig. 1.1 shows the parts of the human gas exchange system together with their functions. On Fig. 1.1, draw a line from each part to its function. One example has already been completed for you.
(a(ii))[2]
State two features of alveoli that make them suited to gas exchange.
(b)[4]
Gas exchange alters the percentages of some gases in the lungs. The pie charts in Fig. 1.2 show how the percentages of gases in the lungs change during one breath. Complete the titles of the pie charts and the key, which shows which gases are represented by the different types of shading.