How many atoms are there in a cubic unit cell having one atom on each corner and two atoms on each body diagonal of a cube?

If the number of atoms per unit cell in a crystal is $2$,the structure of the crystal is:

The coordination number of the sphere in cubic close packed $(ccp)$ structure is

The edge lengths of a simple cubic $(sc)$ and a face-centered cubic $(fcc)$ unit cell are equal. The ratio of the volume occupied by atoms in these two structures is .....

Coordination number of $Zn^{2+}$ in $ZnS$ (zinc blende) is

In an ${A^{+}}{B^{-}}$ ionic compound, the radii of ${A^{+}}$ and ${B^{-}}$ ions are $180 \ pm$ and $187 \ pm$ respectively. The crystal structure of this compound will be: