Blood is regarded as connective tissue because it consists of a non-living fluid in which living cells are present. It has three main functions, namely transportation, regulation and protection. Cells in the blood are of 3 Structure types: red blood cells (erythrocytes), white blood cells (leukocytes) and platelets (thrombocytes). These make up 45% of our blood volume, the rest of the 55% is composed of plasma. Difference between prokaryotic cells vs eukaryotic cells Structure of Red Blood Cells: Red blood cells …