HIV is a virus. Tuberculosis (TB) is a disease caused by a bacterium.
Scientists studied two groups of people for one year. One group was infected with HIV and the other group was not.
The Table shows the results.
Table
| Group | Number of people studied | Number of people who developed TB in one year |
|---|---|---|
| not infected with HIV | 20 000 | 40 |
| infected with HIV | 5000 | 250 |
Calculate the percentage of people infected with HIV who developed TB.
Calculate how many times more likely people infected with HIV were to develop TB than people not infected with HIV.
Explain why people infected with HIV are more likely to develop TB.
112 exam-style questions on Edexcel GCSE Biology 5.1 Health and communicable disease, covering 5.1.1 Communicable and non-communicable diseases, 5.1.2 Disease susceptibility interactions, 5.1.3 Pathogens as disease-causing organisms, 5.1.4 Common infections, 5.1.5 Spread and prevention of pathogens, 5.1.6 Lifecycle of a virus, and 5.1.7 Spread and prevention of STIs. Each one has a worked solution and a mark scheme showing where the marks go.