Since Alai is hitting each with a hammer, the physical property which he must be comparing on the two materials must be hardness. Solubility can be tested when you put them in a solvent. Odor can be tested with smell. Conductivity can be tested with electricity. Hardness can be tested with its resistance to the force that hits it.
The primary greenhouse gases are water vapor, carbon dioxide, methane, nitrous oxide, and ozone. So, the correct answer among these options is water vapor, that is considered to be a greenhouse gas.
<span>polar, Hadley, Ferrel, polar, Hadley, Ferrel. I hope this helps you.</span>
