Differentiate the meanings of the terms homozygous and heterozygous.

The prefix homo means same, so
homozygous means that the organism has two alleles that are the same for a particular
trait.  The alleles could be both dominant (BB) or they could be both recessive
(bb). 

The prefix hetero means
different, so heterozygous means that the organism has two alleles that are different
for a particular trait.  This means that the organism will have one dominant and one
recessive allele (Bb) for the particular trait.