What is the order of these in density iron and carbon dioxide and water?

In terms of density, iron is the densest of the three, followed by water, and then carbon dioxide. Iron has a density of about 7.87 g/cm³, while water has a density of approximately 1 g/cm³ at standard conditions. Carbon dioxide, in its gaseous state at standard temperature and pressure, has a much lower density of about 0.00198 g/cm³. Therefore, the order from highest to lowest density is iron, water, and carbon dioxide.