What makes a trait dominant or recessive?
What do you mean what makes it dominant or recessive? Dominant trait needs to have only one allele with this trait to be expressed; recessive needs both. Dominant traits tend to be more common because you only need one allele for it. Recessive are less common because it is hard to find two heterozygous people with the same recessive allele that will just happen to combine during fertilization. If both parents are homozygous recessive for a particular trait then it will show up in all children of course.
