In the cubic close packing, the unit cell has ......... .
| 1. | 4 tetrahedral voids each of which is shared by four adjacent unit cells. |
| 2. | 4 tetrahedral voids within the unit cell. |
| 3. | 8 tetrahedral voids each of which is shared by four adjacent unit cells. |
| 4. | 8 tetrahedral voids within the unit cells. |
