Final answer:
The human X and Y chromosomes determine an individual's sex. Females have two X chromosomes (XX), while males have one X and one Y chromosome (XY). The X and Y chromosomes are not the same size and do not have the same number of genes.
Step-by-step explanation:
The human X and Y chromosomes determine an individual's sex. Females have two X chromosomes (XX), while males have one X and one Y chromosome (XY). The X and Y chromosomes are not the same size and do not have the same number of genes. The X chromosome is larger and carries about 2,000 genes, while the Y chromosome is smaller and carries fewer than 100 genes, with only a single Y chromosome gene, called SRY, determining male development.