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
Complement attaches to immunoglobulin at ?
assistant
The correct answer is  Ans. is 'd' i.e., Fc fragment . Fc fragment is composed of the carboxyterminal. It determines the biological activity such as complement fixation, placental transfer, skin fixation and catabolic rate. CH-2 of Ig G and CH, of IgM bind to C1q poion of CI.