② The blood glucose concentration of healthy people rises half an hour after meals, so blood glucose will flow out of blood vessels and enter liver cells to form glycogen storage, so the direction of glucose movement in liver tissue is mainly reflected in 3 and 4.
(2) The internal environment consists of extracellular fluid such as tissue fluid, plasma and lymph. Because the protein content of milk powder with large head is almost zero, long-term consumption will directly lead to the decrease of plasma protein, plasma osmotic pressure, water permeability and tissue fluid, thus causing tissue edema.
So the answer is:
(1)① urea and carbon dioxide? ②D
(2)a、b、c？ Aortic second sound