Which of the following is an example of a dominant trait?

Brown eyes are an example of a dominant trait because they exhibit dominance over the trait for blue eyes. In terms of genetics, traits are often categorized as dominant or recessive based on their expression in individuals. The brown eye color is determined by a dominant allele, while blue eye color is associated with recessive alleles.

In human genetics, an individual who has at least one brown eye allele (from either parent) will typically express the brown eye phenotype. This means that even if the individual carries one blue eye allele, the presence of the brown eye allele will mask the expression of the blue eye trait, resulting in brown eyes.

The other options represent recessive traits or conditions: blue eyes require two recessive alleles to be expressed, O blood type is a recessive blood group, and albinism is due to a recessive allele affecting melanin production. Therefore, brown eyes stand out as the dominant trait among the choices provided.