_ In a ball mill, the volume occupied by the balls (when the mill is stopped) is about __________ percent of the volume of the mill.$?

_ In a ball mill, the volume occupied by the balls (when the mill is s

1.	_ In a ball mill, the volume occupied by the balls (when the mill is stopped) is about __________ percent of the volume of the mill.$?
A.	35
B.	50
C.	70
D.	85
Answer» C. 70