Chapter #12. Blood. 12.1. Blood is a type of connective tissue whose cells are suspended in a liquid material. 12.2. Whole blood is: Slightly heavier than water 3 to 4 times more viscous (resistance to flow) Blood cells form mainly in the red bone marrow.
Blood cells form mainly in the red bone marrow.
Blood also contains cells (RBC and WBC) and cell fragments (platelets) called formed elements.