______ are the additional types of bones that are not included in classification by shapes.
A. sutural bones
B. wormian bones
C. sesamoid bones
D. collar bones
查看答案
The following statements , _____, illustrate the functions of calcium.
A. nerve cells need calcium for nerve impulse conduction
B. muscle needs calcium to contract
C. blood needs calcium to clot
D. bone needs calcium to make itself hard
If the hemostasis maintained between the action of osteoblasts and osteoclasts is broken, what might happen?
A. The surplus of calcium in the bone may form spurs.
B. A loss of too much calcium weakens the bones.
C. A loss of too much calcium might cause the bone to break easily
D. if bone loses two much tissue, it may become very flexible.
What are the influential factors that affect normal bone growth?
A. hormones
B. minerals
C. vitamins
D. enzymes
社会存在是指社会的物质生活条件,它有多方面的内容,其中对人类社会存在和发展起决定作用的是( )
A. 社会形态
B. 地理环境
C. 人口因素
D. 物质资料的生产及其生产方式
微信支付 
支付宝支付