Blood group $O$ has:

The blood cell that secretes histamine,serotonin,and heparin is

Even though a donor $X$ and a recipient $Y$ belong to the same blood group,transfusion of blood leads to agglutination. This is because

When whole blood is stored with an anticoagulant at $4^{\circ}C$,the $K^+$ ions move out from the $RBC$ into the plasma. The most likely reason for this is that

Between persons of which two blood groups is the blood transfusion not possible?

To prevent blood clotting, donor blood is treated with $..........$.