(a(i))[3]
Explain how the cells visible in the capillary in Fig. 3.1 may be recognised as red blood cells.
(a(ii))[2]
Capillaries are surrounded by tissue fluid. Outline the ways in which tissue fluid differs in composition from blood.
(b(i))[3]
Describe how mean percentage saturation of haemoglobin with oxygen and mean haemoglobin concentration in blood change as altitude increases.
(b(ii))[3]
With reference to Table 3.1, suggest how people living at high altitude can keep the oxygen concentration in blood leaving the lungs similar to that of people at sea level.