Final answer:
The density of the Sun is most similar to that of water but we know the Sun is not made of water because of its composition and the reactions occurring in its core. Comparatively, iron is denser and hydrogen and air are less dense than the Sun.
Step-by-step explanation:
The density of the Sun is most similar to that of water. The Sun has an average density of about 1.41 g/cm³, which is close to the density of water at 1 g/cm³.
However, we know the Sun is not made of water because it is a massive ball of plasma, consisting primarily of hydrogen and helium, undergoing nuclear fusion. The high temperatures and pressures at the Sun's core make it impossible for water to exist there. Moreover, the Sun emits a significant amount of light and heat, which wouldn't be possible if it were made of water or ice.
The density of iron is another comparison point, but iron is much denser than the Sun. Air and hydrogen have lower densities compared to the Sun, with hydrogen being the primary component of the Sun and contributing to its overall density together with helium.