Over time, natural selection eliminates individuals with detrimental phenotypes from a population. however, there are several examples in the human population in which harmful genetic polymorphisms are maintained. why? a. individuals with two wild type alleles have advantages over individuals carrying the harmful allele. b. individuals with two harmful alleles have advantages over individuals carrying one copy of the harmful allele. c. homozygous individuals have some other advantage over individuals with two wild type alleles. d. heterozygous individuals have some other advantage over individuals with two wild type alleles.

stratosphere: as the altitude increases, the air temperature increases. the stratosphere has a layer of ozone, called the ozone layer. this layer absorbs most of the ultraviolet radiation from sunlight. this results in the stratosphere being warmer.

your spelling is a little off : ]

evidence and logical support is essential for a scientist to do in order to maintain credibility. this is because no one can believe without any logic and without any evidence.hence a scientist can maintain credibility by proving himself and by answering logically so experiments prove very beneficial. logical hypothesis give conclusion which is acceptable. therefore, there are two main factors to maintain credibility by a scientist is evidence and logical support.