<prompt> Poo-caval anastomosis is seen between:In the rectum: superior rectal vein and inferior rectal veinAt the umbilicus: poal vein and accessory hemiazyogs veinAt the esophagus: left gastric vein and paraumbilical veinAt the liver: poal vein renal azygos vein  <response>: A i.e. In the rectum - superior rectal vein inferior rectal vein 