What type of chromosomes determine a female biological sex?

The determination of biological sex in humans is primarily reliant on the presence of specific sex chromosomes. In females, the typical chromosomal composition is characterized by having two X chromosomes. This XX configuration is fundamental to the development of female primary and secondary sexual characteristics, as the genes located on the X chromosomes play crucial roles in various physiological processes.

In contrast, the male biological sex is determined by the presence of one X and one Y chromosome. The Y chromosome carries genes essential for male development, including the SRY gene, which initiates the formation of male reproductive structures. The other options presented either reflect configurations not typically found in biological females or imply sex determination mechanisms that do not exist in humans. Thus, the presence of two X chromosomes distinctly defines the biological sex as female.