Pick the correct one

The correct option is "Blood = Plasma + RBC + WBC".

Let's understand the composition of blood and other body fluids step-by-step to see why this option is correct and why the others are incorrect:

1. Composition of Blood:
Blood is a specialized fluid connective tissue that consists of a liquid matrix called plasma and formed elements (blood cells).
The components can be simplified as:
Blood = Plasma + Formed Elements (Red Blood Cells + White Blood Cells + Platelets)
Therefore, the representation Blood = Plasma + RBC + WBC correctly captures the primary components of blood (plasma and the major cellular components, Red Blood Cells and White Blood Cells).

2. Why the other options are incorrect:
• Lymph = Plasma + RBC + WBC: This is incorrect because lymph is a colorless fluid that lacks red blood cells (RBCs) and some large proteins. It primarily contains plasma and white blood cells (especially lymphocytes).
• Plasma = Blood - Lymphocytes: This is incorrect because lymphocytes are just one type of white blood cell. Removing only lymphocytes from blood would still leave RBCs, other WBCs, and platelets, which is not plasma. Plasma is obtained by removing all cellular elements (RBCs, WBCs, and platelets) from the blood.
• Serum = Blood + Fibrinogen: This is incorrect. Serum is actually plasma from which the clotting factors (mainly fibrinogen) have been removed. The correct relation is Serum = Plasma - Clotting factors (like Fibrinogen).