What is typically involved in a blood transfusion?

The transfer of blood from a donor is a crucial component of a blood transfusion. During this procedure, blood or specific components of blood (such as red blood cells, plasma, or platelets) are collected from a donor and given to a recipient who requires additional blood for various medical reasons, such as surgery, trauma, or certain medical conditions like anemia. This process is designed to restore the blood volume or improve the blood's ability to function effectively in the body.

The other options, while related to medical procedures, do not accurately describe the core elements of a blood transfusion. Medication administration, infusion of glucose, and introduction of saline solution are distinct practices that serve different purposes in medical care and do not involve the direct transfer of blood from one individual to another, which is the defining characteristic of a blood transfusion.