Mendel’s law of dominance supports that: One person dominates over another. A copy of a gene rides over another. When the unit factors are dissimilar one is dominant and the other is recessive. When unit factors are similar one is dominant and the other is recessive. Dissimilar unit factors are dominant. Solution Answer: When the unit factors are dissimilar one is dominant and the other is recessive. Explanation: Example.. Tt(dissimilar factors)= T is dominat and t is recessive. TT (similar factors)= Both dominant tt (similar factors)= Both recessive.