system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Characteristic feature of amoebic ulcer -a)  Flask shapedb)  Undermined edgesc)  Rolled up edged)  Punched out
assistant
The correct answer is  Amebiasis most frequently involves the cecum and ascending colon, followed in order by the sigmoid, rectum and appendix.
The ulcerative lesions develop undermining of margins of the ulcer due to lytic action of the trophozoites.
Ulcer has a flask shaped with a narrow neck and broad base.