Identify each unit cell as a simple cubic (or primitive-cubic), body-centered cubic, or face-centered cubic unit cell. Face-centered cubic is also known as cubic close‑packed. The first unit cell is a six sided cube with a sphere on each corner and a line along each edge of the cube connecting the center of each sphere with the centers of three other spheres. The second unit cell is a six sided cube with a sphere in the center of the cube, a sphere on each corner, and a line along each edge of the cube connecting the center of each corner sphere with the centers of three other corner spheres. The third unit cell is a six sided cube with a sphere in the center of each face, a sphere on each corner, and a line along each edge of the cube connecting the center of each corner sphere with the centers of three other corner spheres. Dashed lines connect each face sphere with the sphere on the opposite face.