(a(i))[3]
Describe the way macrophages engulf bacteria.
(a(ii))[3]
Explain the roles of lysosomes in cells such as macrophages.
(b(i))[3]
Calculate the percentage change in the number of new TB cases in the USA from 1993 to 2018. Show all your working.
(b(ii))[2]
Use Fig. 2.2 to describe the pattern in the number of new TB cases in the USA between 1993 and 2018.
(c)[1]
Suggest an advantage of calculating the number of new cases per $100\,000$ each year in the prevention and control of TB across the world.
(d)[2]
State two reasons why reducing the number of TB cases worldwide is difficult.