<prompt> Ascent of horse shoe shaped kidney is prevented bySuperior mesenteric aeryInferior mesenteric aerySuperior mesenteric veinInferior mesenteric vein  <response>: Initialy in IULintrauterine life kidneys are present in iliac fossa , Kidney has to reach the level of renal aery which is prevented by inferior mesenteric aery which is a branch of abdominal aoa. Fusion of right and left kidney occurs to form a U shaped structure at the level below inferior mesenteric aery. 