| Date | May 2012 | Marks available | 1 | Reference code | 12M.1.HL.TZ2.18 |
| Level | Higher level | Paper | Paper 1 | Time zone | Time zone 2 |
| Command term | Identify | Question number | 18 | Adapted from | N/A |
Question
What type of process causes antibiotic resistance to develop in bacteria?
A. Competition with viruses
B. Overproduction of offspring
C. Evolution due to environmental change
D. Response by bacteria to an epidemic
Markscheme
C
Examiners report
Some teachers felt that answers B and C were both correct. Overproduction of offspring (B) is part of the Darwinian explanation of natural selection, but it does not in itself cause bacteria to develop resistance to antibiotics. The answer was evolution due to environmental change (C). Evolution is the process that causes antibiotic resistance to develop and the presence of antibiotics drives this. If a candidate thinks that there are two answers that are both partly or both wholly correct, they should always pick the best of the two answers. That was certainly C in this case. In fact few candidates chose B and a more popular wrong answer was D; response by bacteria to an epidemic.
