Discuss how variations within the population affect survival and fitness using an influenza outbreak as a model to support your explanation.

During an influenza outbreak, many people get infected and die. However, part of the population acquires immunity and survives. This is due to variations in the genotype and phenotype among individuals in the population. Probably a particular phenotype confers resistance to influenza. Therefore, this population is able to grow and develop to maturity and reproduce. Their genes are therefore passed over to subsequent generations.