The correct answer is "alleles." Genes are segments of DNA that contain the instructions for building and operating an organism. Each gene can have different forms or variants, known as alleles. Alleles are alternative versions of a gene that result in variations in specific traits or characteristics. For example, the gene for eye color can have alleles for blue, brown, green, or hazel eyes. These alleles give rise to different phenotypes, which are the observable traits or characteristics determined by the combination of alleles. Therefore, while genotypes refer to the specific combination of alleles for a particular gene, phenotypes are the physical or observable outcomes resulting from the expression of those alleles.
