DOMINANT ALLELES OVERRULE RECESSIVE ALLELES.
Only dominant traits are shown in a person's physical appearance. Dominant alleles are capital letters while recessive alleles are lower case letters.
Homozygous genes are two of the same type of allele together. Heterozygous genes are each type of an allele together, involving a lowercase (the recessive trait) and is not physically present.
PUNNET SQUARES ARE USED TO SHOW THE POTENTIAL GENOTYPES AND PHENOTYPES the OFFSPRING CAN RECEIVE.
Incomplete dominance is when the traits blend due to the presence of multiple dominant genes. These two traits share the dominance and as a result, a mixture of these traits are expressed.
Codominance is when both alleles are equal and creates variation in the organisms appearance. In other words, one trait does not want to give up its "throne" to the other so they just share the dominance. Both traits can be shown but they are not mixed.