Adult female monkeys from one population breed with male monkeys of a nearby population. The introduction of new alleles into the first population's gene pool is an example of

The introduction of new alleles into the gene pool of the first population, from another population, is an example of gene flow.

Explanation:

In population genetics, gene flow consists of the passage or transfer of gene alleles between populations, a process that is related to the migratory dynamics of a population.

When gene flow occurs, a population can gain new genetic material or lose it, which is reflected in traits or characteristics of that population.

If an adult monkey interbreeds with an adult monkey from another population there will be a gene flow that will probably introduce specific trait information into the gene pool of their respective populations.

where is the scientific experiment?

2%? i tried finding the exact sorry if it's not 100% correct ; -;