Joe has a white cat named Sam. When Joe crosses Sam with a black cat, he gets white kittens and black kittens. When

Joe has a white cat named Sam. When Joe crosses Sam with a black cat, he gets ½ white kittens and ½ black kittens. When the black kittens are interbred, all of the kittens they produce are black. On the basis of these results, would you conclude that white or black coat color in cats is a recessive trait? Explain your reasoning.