Explain why molecular compounds have a lower melting point than do ionic, metallic, or covalent network substances

The agent of mechanical weathering in which rock is worn away by the grinding action of other rock particles is call

As air becomes more dense, (select all that apply) o. air weighs less o. gas molecules are closer together o. air is colder o. air weighs more o. gas molecules are further apart o. air is hotter

What human activity increases beach erosion?