Q1. Immunosuppressants such as .......... prevent transplanted organs from being rejected in recipients.
A Cyclosporine Correct
B Calcitonin
C Thrombin
D Aspirin
Explanation
Cyclosporine is an immunosuppressant used after organ transplantation because it reduces immune responses that can attack the transplanted organ. It acts mainly by suppressing T-cell activity, so it fits the blank directly. Calcitonin is a hormone involved in calcium regulation and is not used to prevent graft rejection. Thrombin is part of the blood-clotting process, not immune suppression. Aspirin is an analgesic and antiplatelet drug; it may affect clotting, but it is not the classic transplant anti-rejection immunosuppressant asked for here.