1.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.
1.人体在生命运动各种营养(水、无机盐、蛋白质、
类脂肪、维生物矿物质,氧气),
吸收
通过血液循环系统。