Question $21(4$ points$)$

Which of the following statements about Atomic Packing Efficiency $($APE$)$ are true?

$($Select all that apply$)$

Select $4$ correct answer$($s$)$

APE of BCC structure is $68\%$

APE indicate the strongness the of the unit cell

APE indicates how well the atoms are packed in the unit cell

APE is the ratio of the volume occupied by the atoms to the total volume of the unit cell.

APE of FCC and HCP structures is $74\%$