Final answer:
Gases are measured in grams per liter (g/L) while solids and liquids are measured in grams per cubic centimeter (g/cm³).
Step-by-step explanation:
The density of gases is typically described using the units of grams per liter (g/L). For example, the density of air at sea level and 15 °C is approximately 1.224 g/L. On the other hand, the densities of solids and liquids are often reported using the units of grams per cubic centimeter (g/cm³). For instance, the density of water at 4 °C is 1.00 g/cm³.