<prompt> What is true about ulcerative colitis?Involves rectum and then whole colon backwardsInvolves only colonSkip lesions seenIleum not involved  <response>: Ans. is b i.e., Involves rectum and then whole colon backwards o Ulcerative colitis involves the rectum and extends proximally in a retrograde fashion to involve the entire colon pancolitis in more severe cases. 