A planetary body's average (bulk) density is strongly influenced by the relative size and composition of its metallic core versus its silicate mantle and crust. A smaller or less iron-rich core lowers the overall average density.
The Moon's average density (~3.34 g/cm³) is notably lower than Earth's (~5.51 g/cm³). This is primarily because the Moon has a very small metallic (iron-rich)...
Full option-by-option analysis available to enrolled students.