The XX chromosome pair is one of the two sex chromosome combinations in humans and many other organisms. Females typically have two X chromosomes, which play a crucial role in determining female biological characteristics and functions. Each X chromosome carries numerous genes that are essential for various bodily processes. In contrast, males usually have one X and one Y chromosome (XY). The presence of the Y chromosome triggers male development, while the two X chromosomes in females contribute to traits such as color vision and blood clotting. Understanding the XX chromosome is vital in genetics and reproductive health.