Feather color in a bird was traced to a single gene. six variations of feather color could be observed across the bird population. which of the following could account for so many variations? . a there are two alleles that interact through incomplete dominance.. b feather color is a polygenic trait.. c multiple alleles for feather color are present in the population.. d all of the above

The answer is C Multiple alleles for feather color are present in the population.

An allele is one of two or more alternative forms of a gene. Since feather color in a bird was traced to a single gene, the trait is a monogenic and not a polygenic trait (choice b drops off). Further, there are 6 variations of feather color which are  controlled by one gene. That means there are 6 variations of the gene. And since the alleles are alternative forms (or variations) of the gene, there are 6 different alleles for feather color.

Carbon dioxide is the correct answer