What is the term for the liquid component of blood?

Plasma is the term for the liquid component of blood, making it the correct answer to this question. Plasma accounts for about 55% of the total blood volume and is primarily composed of water, which makes up around 90-92% of its content. It also contains essential proteins, nutrients, hormones, waste products, and electrolytes that are crucial for various bodily functions, including transportation of cells and nutrients, maintaining blood pressure, and regulating body temperature.

Serum, while it may seem like a possible answer, is the liquid that remains after the blood has clotted, meaning it does not contain clotting factors such as fibrinogen, which are present in plasma. Whole blood includes both the liquid and cellular components, meaning it consists of plasma along with red blood cells, white blood cells, and platelets. Hemoglobin is a protein found within red blood cells and is responsible for transporting oxygen, rather than a component of blood in its liquid form. Therefore, understanding the functions and components of blood clarifies why plasma is the correct answer when identifying the liquid part.