Answer:
1. The main physiological role of red blood cells (RBCs), or erythrocytes is to transport of gases (O2, CO2) from the lung to the tissues and to maintain systemic acid/base equilibria. In addition, RBCs are well equipped with antioxidant systems, which essentially contribute to their function and integrity.
2. In humans, it includes plasma (the liquid portion), blood cells (which come in both red and white varieties), and cell fragments called platelets. Plasma is the main component of blood and consists mostly of water, with proteins, ions, nutrients, and wastes mixed in.
3.Blood is a body fluid in humans and other animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells.