安全色规定为红、兰、黄、绿四种颜色，其中黄色是禁止和必须遵守的规定。
参考答案：错
A nursery sells trees of different types and heights. Suppose that 75 pine trees are sold for planting at City Hall. These 75 trees average 60 inches in height with a standard deviation of 16 inches. Using this information, construct a 95 percent confidence interval for the mean height of all trees in the nursery:（）
A. 60±1.96(16).
B. 0.8±1.96(16).
C. 60±1.96(1.85).
有机整体的中心是（）
A.肝
B.脑
C.心
D.五脏
E.经络
