<prompt> Plica circularis is absent in:DuodenumJejunumProximal ileumDistal ileum  <response>: Luminal surface of small bowel reveals mucosal folds called plicae circulares Numerous in the proximal jejunumIt decreases in distal small bowelAbsent in terminal ileum Aggregates of lymphoid follicles are highest in the ileum Peyers patchesPeyers patches are more prominent during infancy and childhood. Ref: Sleisenger, E - 9, P-1615 