Identify A, B, C, and D for the given image.
A. White blood cells, B. Red blood cells, C. Platelet, D. Nucleus
Blood is a fluid connective tissue of the human body. It contains plasma as a liquid matrix and cells make up the cellular component. Blood has RBCs, WBCs and Platelets. WBCs are of different types depending on the shape of the nucleus. RBCs carry oxygen through haemoglobin present in them, WBCs help in fighting infections and platelets help in blood clotting.