Asingle grain of sand occupies a volume of about 0.004 cubic millimeters. based on your previous answer,
how many grains of sand are on earth's beaches?

The answer to this is the 3rd choice!

Answerδh > 0explanationc₆h₆  (s)  → c₆h₆ (l)if you are changing it from a solid to a liquid, you are pretty much melting the solid. this requires heat energy. therefore, the reaction is endothermic (takes in energy); the system enthalpy increases as the reaction proceeds: δh > 0.