In what part of the blood sample would you expect to find the majority of proteins?

The majority of proteins in a blood sample are found in the plasma, which is the liquid component of blood that remains after the cells have been removed. Plasma is composed of about 90% water and contains a variety of important proteins, including albumin, globulins, and fibrinogen. These proteins serve crucial roles in maintaining osmotic pressure, immune function, and blood clotting.

In contrast, the buffy coat primarily contains white blood cells and platelets, while red blood cells lack significant protein content. Serum is the liquid that remains after blood has clotted and is devoid of clotting factors; although it does contain some proteins, its protein content is lower than that found in plasma. Therefore, the plasma is indeed the component where the majority of proteins reside, making it the correct answer.