How can gene flow result in changes in allele frequencies

"Both processes allow for gene flow between populations. Gene flow may changethe frequency and/or the range of alleles in the populations. If populations are large, migration may have little or no effect on allele frequency. However, if populations are small, migration may have a big impact on allele frequency.Oct 22, 2012"-www.slideshare.net/tammi-1990/factors-affecting-allele-frequencies

1. true.2. true.3. true.4. false.5. true.the concept of darwin's theory of evolution involves the idea that there are limited resources in a given living environment and that the organisms which live within have variations in their genetic make up due to random mating. the ones with beneficial genetic variations can express certain traits which give them an upper hand in surviving and reproducing in the said environment compared to ones who may have a more disadvantageous variation in traits. over time, the organisms with an upper hand will survive and reproduce more frequently and pass on their beneficial genes while the others die. the result is evolution, where we observe (usually, but not always) eventually, phenotypic distinct changes.