False. Natural selection, genetic drift and gene flow all act to change allele frequencies.
True. If allele frequencies change, it indicates that certain traits or alleles are being favored or selected for in a population. This process is known as natural selection, which is one of the driving forces of evolution. Natural selection acts on the variation within a population and results in the increased or decreased frequency of certain traits or alleles over time. To determine if allele frequencies have indeed changed and whether natural selection is at play, one would need to collect and analyze data on the population's genetic composition, such as through genetic studies or surveys.
