If parents supplied different alleles for a certain trait to their offspring which of the following terms would be used to describe the offspring a. recessive b. dominant c. homozygous d. heterozygous

The correct answer is D Heterozygous

Alleles are different variants of the same gene, located at the same place in the genome, the same locus.
Since we have two copies of all of the genes, one inherited from our father and other inherited from our mothers, we have two copies or alleles of the same gene.
If both of our parents pass us the same allele, the same variant of a gene, we would be Homozygous for that gene.
In the case that our parents pass to us two different alleles, we would be Heterozygous. 

True, the united states of America was responsible for the Human Genome Project (HGP)