Final answer:
The components that help determine blood type are the antigens found on the surface of red blood cells. (option 4)
Step-by-step explanation:
Antigens located on the surface of red blood cells are responsible for determining a person's blood type. The four main blood types, A, B, AB, and O, are characterized by the presence of A and/or B antigens or the lack thereof. Antibodies in the blood plasma will react against foreign antigens which is crucial in blood transfusions. Blood type is a genetic characteristic and the well-known blood type systems are the ABO and Rhesus systems. There are four main blood types, which are A, B, AB, and O. Individuals with type A blood have type A antigens on their red blood cells, while those with type B blood have B antigens. If someone has type AB blood, they possess both A and B antigens, and if they have type O blood, they do not have either antigen.
Blood plasma contains antibodies, which are different from the antigens found on the red blood cells. These antibodies in the plasma will react against antigens that are not recognized as 'self', which is an important consideration for blood transfusions and compatibility.
It is the antigens on the red blood cells that help scientists determine blood type, not the components inside the blood plasma.