Final answer:
The structure of DNA, with its organization into chromosomes and genes, is responsible for the uniqueness of each human.
Step-by-step explanation:
The structure of DNA is responsible for the uniqueness of each human. DNA is organized into 46 chromosomes in humans, and each chromosome contains thousands of genes. These genes are responsible for determining different traits, such as skin color, eye color, and bone size. While humans have the same genes, variations in alleles, which are alternative forms of a gene, account for the considerable genetic variation among individuals.