The liquid part of blood is made mostly of

Water

Explanation: The liquid part of the blood is called the plasma. Blood has four components: plasma, red blood cells, white blood cells and platelets. The plasma makes up about 55% of the blood volume. The plasma contains hormones, mineral ions, and proteins. The major plasma protein is albumin. Plasma functions in transporting nutrients, hormones and proteins to the parts of the body where they are needed. The red blood cells function in transporting oxygen to the cells and taking carbon dioxide from the cells to the lungs from where it is exhaled. The white blood cells participate in fighting pathogens and triggering immune response while the platelets plays a major role in blood clotting.