Can someone help me with these three questions!?! It also needs to have work with it!

What is the force of attraction between the particles in a salt crystal

What term is missing from the central region that describes hypotheses, theories, and laws? popular predictable mathematical falsifiable

Which process does not require the presence of a physical substance in order to transfer heat? air in the atmosphere is heated by the ground. this warm air then rises, and cooler air falls. this is an example of what type of process? how is conduction different from radiation?