SORU: boş bırakılan yere parçanın anlam bütünlüğünü sağlamak için getirilebilecek cümleyi bulunuz
Ulcerative colitis is a disease in which extensive areas of the walls of the large intestine become inflamed and ulcerated. Some clinicians believe that it results from an allergic or immune destructive effect, but it could also result from a chronic bacterial infection. ----.