The gene for fur color in rabbits, given that a white-furred rabbit breeds with a black-furred rabbit and all their offspring have gray fur, appears to be an example of incomplete dominance. In incomplete dominance, neither allele is completely dominant over the other, resulting in a heterozygous phenotype that is intermediate between the two homozygous phenotypes. Here, the white fur allele and the black fur allele blend to produce gray fur in the offspring, which is a mix of both parental colors rather than showing one color fully dominant or both colors fully expressed separately (as in codominance)

• Mosaicism is unrelated because it involves different genetic makeup within cells of the same individual, not intermediate phenotype inheritance.
• Codominance would result in offspring showing both black and white patches distinctly, not a blended gray.
• Complete dominance would result in offspring showing only one parent's fur color, not an intermediate color.

Thus, the fur color gene in this scenario exemplifies incomplete dominance.