Introduce the general idea: human body need all kinds of nourishment during the life(such as water, inorganic acid, protein, glycolipin, microbian mineral, oxygen),blood cycle for digestion.
人体在命运动中需要各种营养(水、无
、
白质、
类脂
、
物矿物质,氧气),其消化吸收需通过血液循环系统。