The diameter of the rod is______________?
A. 4 μ m
B. 9 μ m
C. 7 μ m
D. 2 μ m
Previous Post: Inorganic content of enamel is about______________?
A. 4 μ m
B. 9 μ m
C. 7 μ m
D. 2 μ m