固定桥修复的生理基础是()
A.牙槽骨
B.牙槽嵴黏膜
C.基牙代偿力
D.牙周储备力及代偿功能
E.以上均不是
参考答案:D
仅在体内有抗凝血作用的药物是()
A.肝素
B.华法林
C.达比加群酯
D.尿激酶
E.阿哌沙班
Which of the following most accurately describes the shape of the average fixed cost (AFC) curve The AFC curve:()
A. is always below the average variable cost curve.
B. has the same shape as the average total cost curve.
C. becomes flatter as output increases.