A watery fluid with proteins, other molecules and dissolved minerals that constitutes half the blood volume and provides a fluid environment for other blood components is called what?

• A. Plasma
• B. Serum
• C. Platelets
• D. Fibrinogen

Answer: (A)

The liquid component of blood that carries water, proteins, minerals, and other substances and provides the medium in which blood cells live is plasma. It makes up roughly half of blood’s volume and contains clotting factors, nutrients, hormones, and waste products, all circulating to keep the body's systems working. After blood clots, the remaining fluid is called serum, which lacks some clotting factors like fibrinogen, so serum isn’t the same as plasma. Platelets are small cell fragments that help with clotting, not a fluid component. Fibrinogen is one of the clotting proteins found in plasma that can form fibrin during clot formation, so it’s a part of plasma but not the fluid itself.