Final answer:
A human with a single X chromosome and no Y chromosome is considered to have Turner syndrome, a genetic condition associated with a female phenotype and symptoms like short stature, certain physical anomalies, and sterility due to the absence of a second sex chromosome.
Step-by-step explanation:
A human with a single X chromosome and no Y chromosome would be considered to have Turner syndrome, which is an X-chromosome abnormality. Turner syndrome corresponds to a phenotypically female individual with certain physical and developmental characteristics. These individuals often exhibit short stature, webbed skin in the neck region, hearing and cardiac impairments, and sterility. This condition occurs due to the absence of all or part of a second sex chromosome.
In cases where individuals carry an abnormal number of X chromosomes, typically one X chromosome will become inactivated in each cell to compensate for the excess genetic information. This process is seen in Klinefelter syndrome, where males have an extra X chromosome. However, in Turner syndrome, the lack of a second X chromosome leads to the physical features and health issues characteristic of the syndrome, since there is no additional X to undergo inactivation.