Which of the following is an example of a body-centered cubic cell?

At room temperatures, elements lithium, sodium, rubidium, barium, vanadium, chromium and iron have structures that can be described as a body center cubic packing of spheres. The packing fraction of a body center cubic cell is 0.68.

metric time was an attempt to create a standard unit of time based off of 10, but it never took off an is not included in the metric system (si)

ca has a crystalline lattice with positive ions (since it is a metal, metals are positively charged) and electrons flow freely in its structure since the ca atoms have a large nuclear radius so the electrons are not tightly held, therefore the electrons can flow freely since they are not being highly attracted by the nucleus. moreover, one of the properties of metals are that they are conductors of electricity, thus proving ca is the element.