CAIE A Level Biology 9700 · Infectious diseases
Tuberculosis (TB) is caused by the bacterium Mycobacterium tuberculosis. In a low-income urban community with overcrowded housing, high rates of malnutrition, and limited access to healthcare, the incidence of TB is significantly higher than in wealthier areas.
Outline the biological, social, and economic factors that explain why TB spreads more readily in such crowded or poor conditions.
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Outline means: Give the main points briefly. Less detail than describe, but every key step has to be there. One short line per step, in order. The marks are for coverage, not depth.
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