(a)[4]
Explain how the human gas exchange system is protected from pathogens.
(b)[4]
Explain how vaccination provides protection against transmissible diseases.
(c)[2]
Explain why antibiotics are ineffective against viral diseases.
(d(i))[3]
Describe the differences between the percentages of males and females in country A who smoke, as shown in Fig. 4.1.
(d(ii))[6]
Discuss the evidence for and against this statement: ‘The changes in the percentage of the population that smoke tobacco, and the deaths from lung cancer per 100000, show the same pattern in males and in females.’ Use the information for country A in Fig. 4.1 and country B in Fig. 4.2 in your answer.