The human erythrocyte loses its nucleus and mitochondria during differentiation. It therefore relies on _________ alone for its supply of ATP. The lactate produced by glycolysis returns to the liver, where gluconeogenesis converts it to glucose, to be stored as glycogen or recirculated to peripheral tissues. The erythrocyte has constant access to glucose in the bloodstream.

The way of digester mixing: ( ). A: The digester gas is compressed and injected into the liquid through lances or diffusers. B: Mechanical mixers, usually slow speed turbines, create liquid motion inside the digester. C: A combination of above three ways. D: The liquid contents are recirculated by pumping them from one location to another.