Which of the following is an example of gene flow that can change allelic frequencies in a population?

• A. Individuals with one phenotype leave more offspring because that phenotype increases survival.
• B. Migrants from a neighboring population enter and interbreed, introducing new alleles into the population.
• C. A mutation arises in a gene within the population, creating a new allele.
• D. A random hurricane drastically reduces population size, changing allele frequencies by chance.

Answer: (B)