In genetics when an organism is heterozygous that means that it contains 2 different alleles for a specific gene, heterozygous refers to the genotype
Homozygous means the organism carries 2 of the same alleles.
For example there are two alleles for the gene of eye color
B- is the dominant allele for brown eyes
b- is the recessive allele for blue
So if a person's genotype is like Bb then he is heterozygous
but if he is like BB or bb then he is homozygous
