9. In cattle, a dominant gene (N) results in a deep notch in each ear. A recessive gene (u) results, when in the homozygous condition, in an udder abnormality. A farmer has a herd of cattle in which some of the individuals have notched ears and some have abnormal udders. He desires to rid his herd of these characteristics. Which would be the easiest to eliminate from the herd? How should he go about eliminating each?