A new disease spreads through a population of wild sunflowers. After many generations, an allele for resistance to the disease is more common in the population. Which sequence of events could account for this change?
A random mutation produced the resistance allele before the disease arrived, and resistant plants then left more offspring than susceptible plants.
The disease caused mutations that produced the resistance allele, and resistant plants then left more offspring than susceptible plants.
Plants that needed protection produced the resistance allele during infection, and then passed this allele on to their offspring.
A random mutation produced the resistance allele before the disease arrived, and resistant plants then lived longer without leaving more offspring.
85 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.