An antibiotic is added to a population containing resistant and non-resistant bacteria. Resistant bacteria survive and reproduce. Which change is most likely after several generations with this antibiotic?
The proportion of non-resistant bacteria increases within the population.
The antibiotic concentration increases as resistant bacteria reproduce rapidly.
The proportion of resistant bacteria increases within the population.
The mutation rate increases because bacteria need antibiotic resistance.
44 exam-style questions on Edexcel GCSE Biology 4.1 Evolution and natural selection, covering 4.1.1 Work of Darwin and Wallace and 4.1.2 Resistant organisms and evolution. Each one has a worked solution and a mark scheme showing where the marks go.