D. Cystic hygroma, flat nasal profile, and webbed neck
Turner syndrome, also known as 45,X or monosomy X, is a genetic condition that affects females and is caused by the absence or partial absence of one of the X chromosomes. The characteristic features associated with Turner syndrome include a cystic hygroma (a fluid-filled swelling typically seen in the neck), a flat nasal profile, and a webbed neck (extra folds of skin on the sides of the neck). These features are commonly observed in individuals with Turner syndrome. Infantile sexual characteristics (referring to delayed or incomplete sexual development), duodenal atresia (a blockage in the small intestine), mild ventriculomegaly (enlargement of the brain's ventricles), and echogenic bowel (increased echogenicity or brightness of the bowel seen on ultrasound) are not specifically associated with Turner syndrome. Short stature is another common feature of Turner syndrome, but it is not included in the given set of characteristics. Therefore, option D best represents the set of characteristics associated with Turner syndrome
