Final answer:
Turner Syndrome symptoms occur due to the haploinsufficiency of genes on the single X chromosome that is not sufficient for a normal phenotype, resulting in characteristic physical and developmental challenges.
Step-by-step explanation:
Why females with Turner Syndrome present symptoms even though X-inactivation does not occur is c) Haploinsufficiency of genes on the X chromosome. Turner Syndrome is caused by the complete or partial absence of one of the two X chromosomes, typically in females, resulting in a 45,X karyotype. This condition is termed monosomy X. Symptoms in Turner Syndrome are not due to the presence of the SRY gene, inactivation of the AR gene, or overexpression of genes on the X chromosome.
Rather, the symptoms are due to haploinsufficiency, where a single copy of a gene is not sufficient to produce a normal phenotype. This leads to developmental problems, as certain critical genes on the missing X chromosome are not expressed at adequate levels. Individuals with Turner Syndrome often display characteristic symptoms such as short stature, webbed neck, hearing and cardiac impairments, as well as sterility due to the non-maturation of sexual organs.