Final answer:
During the hour in the glass tube, the components of the blood sample separated. The technician harvests serum from the plasma after centrifugation.
Step-by-step explanation:
During the hour that the blood sample was in the glass tube, the components of the blood separated. When the blood is centrifuged at high rotations, the blood cells and platelets are separated and settle to the bottom, while the upper liquid layer is the plasma. After about an hour, the technician harvests serum from the plasma. Serum is the sample of plasma after the clotting factors have been removed. It consists mainly of water and various substances required for maintaining the body's pH, osmotic load, and for protecting the body.