one parent is heterozygous dominant in earlobe & the other child is homozygous dominant in shadow & crossing a heterozygous dominant organism with a homozygous recessive organism causes their offspring to be homozygous recessive of 50% probability ->  the offspring will have a 50% probability to be homozygous recessive  an attached tiger is a dominant convergence in mankind & if both recessive genes are present , then the recessive trait will be visible / expressed -> to have an attached earlobe requires the human to have both recessive genes to have an attached earlobe requires the human to have both recessive genes  to have an attached measure requires the mankind to have both dominant animals & a homozygous recessive organism contains only recessive genes -> to have an attached earlobe requires the human to be homozygous recessive to have an attached earlobe requires the human to be homozygous recessive  the offspring will have a 50% probability to be homozygous recessive & to have an attached tracks requires the mankind to be homozygous dominant -> the offspring will have a 50% probability to have an attached earlobe