Which of the following plasma proteins plays a role in blood clotting?

The plasma protein that plays a role in blood clotting is fibrinogen. Here are the steps to understand this:

1. Blood plasma is the liquid component of blood, in which the blood cells are suspended. It makes up about 55% of the body's total blood volume.

2. Plasma is composed of about 90% water. The remaining 10% is made up of various substances, including proteins, glucose, mineral ions, hormones, carbon dioxide, and blood cells themselves.

3. There are three main types of proteins in blood plasma: albumin, globulins, and fibrinogen.

4. Albumin is the most abundant protein in plasma, making up about 60% of the total protein content. It helps to maintain the osmotic pressure of the blood, which is necessary for the proper distribution of body fluids between the blood vessels and body tissues.

5. Globulins make up about 35% of the total protein content. They are involved in various functions, including the transport of lipids and the functioning of the immune system.

6. Fibrinogen makes up about 4% of the total protein content. This protein plays a crucial role in blood clotting. When a blood vessel is damaged, fibrinogen is converted into fibrin by the action of an enzyme called thrombin. Fibrin then forms a mesh-like structure that traps blood cells and platelets, forming a clot and preventing further blood loss.

So, the answer to your question is fibrinogen.