The need for hearing aids pretty much goes hand-in-hand with aging. And yet Medicare doesn't cover them. Hearing aids are considered an elective, and just like with eye glasses, patients are responsible for 100 percent of the bill. Hearing tests are also the responsibility of the Medicare patient. Regulations vary by the state and there may be some exceptions but, overwhelmingly, this statement is true: Older people need hearing aids and glasses and Medicare doesn't pay for them. And it would take an act of Congress to get that to change.
From Wikipedia, the free encyclopedia. Allele frequency, or gene frequency, is the relative frequency of an allele (variant of a gene) at a particular locus in a population, expressed as a fraction or percentage. Specifically, it is the fraction of all chromosomes in the population that carry that allele.
Best Answer: 1. Genetic Drift: This represents random changes in small gene pools due to sampling errors in propagation of alleles. The bottleneck effect and founder effect are prime examples of genetic drift.In either case the number of individuals in a population is drastically reduced distorting the original allelic frequencies. 2. Gene Flow: The movement of alleles into and out of a gene pool.Migration of an organism into different areas can cause the allelic frequencies of that population to increase.he bottleneck effect and founder effect are prime examples of genetic drift. In either case the number of individuals in a population is drastically reduced distorting the original allelic frequencies.