Concept:Agglutination is the clumping together of red blood cells, usually caused by antibody-antigen reactions.
Explanation:During a blood transfusion, if incompatible blood types are mixed, antibodies in the plasma bind to antigens on the transfused red blood cells.
This binding makes the red blood cells stick together in clumps, which is called agglutination.
This process is essentially a form of coagulation, specifically involving red blood cells.
Therefore, agglutination is the coagulation of red blood cells.
Answer:D. coagulation, red blood cell