Final answer:
Gene flow best explains the presence of alleles that lead to a coloration pattern similar to coral snakes in kingsnake populations near (but not in) the range of coral snakes.
Step-by-step explanation:
The process that best explains the presence of alleles that lead to a coloration pattern similar to coral snakes in kingsnake populations near (but not in) the range of coral snakes is gene flow. Gene flow occurs when individuals from one population migrate or breed with individuals from another population, resulting in the exchange of genes. In this case, individuals with the coral snake-like coloration alleles may have migrated into the kingsnake populations, increasing the frequency of these alleles.