A malaria outbreak causing a Lily's frequencies to change is an example of

A malaria outbreak causing allele frequencies to change is an example of natural selection.

Explanation:

Natural selection is a type of selection in which those organisms are favoured to live and reproduce which are better adapted to live in an environment. Due to natural selection, the allele frequencies of a population will tend to change with the passage of time.

When the outbreak of malaria occurs, those organisms which do not catch malaria are able to survive and pass on their characteristics to their offsprings. the other organisms die and do not reproduce. This will cause changes in the allele frequencies.