Dominant and recessive refers to genetics and the expression of certain phenotypes. A dominant trait will be the phenotype of the offspring if a parent passes it on, but a recessive trait will only be shown if both parents posses the trait. In humans, free earlobes are dominant, and attached earlobes are recessive. My friend on the left has the dominant trait of free earlobes, so only one of his parents need the trait for him to have it. My friend on the right has attached earlobes, which ears that both parents had to pass on the recessive trait for him to have that phenotype.