(1) The physiological process A in the figure represents the process that food enters the blood through the digestive tract, which is the absorption of nutrients; Small intestine is the main organ for human body to absorb nutrition. After being absorbed in the small intestine and other places, various nutrients are transported to the whole body with the blood in the inner wall blood vessels.

(2) The physiological processes B and C in the figure represent the gas exchange between the lungs and the outside world, which is realized by respiratory movement; Carbon dioxide produced by tissue cells enters the blood through diffusion.

(3) Hemoglobin in red blood cells has the function of transporting oxygen; Iron and protein are important raw materials of hemoglobin, so in order to prevent the lack of protein in the body, a certain amount of food containing protein and iron should be matched when designing the menu.

(4) Tomatoes, peppers and other fruits and vegetables are rich in vitamin C. Regular consumption can effectively prevent scurvy.

(5) protein can be digested by gastric juice, intestinal juice and pancreatic juice, and protein is finally decomposed into amino acids in the small intestine.

So the answer is: (1) absorption; small intestine

(2) respiratory movement; Diffusion (gas)

(3) Iron

(4) bad blood

(5)3; amino acid