I think answer is
C. Something that can be observed or measured while changing the identity of the substance
Answer:
I know that Aerogel is the lightest metal in existence, but I don't think it would help much with your answer. I mean you can give it a try?
Answer:
Atoms making liquids have less attraction than solids, but more than gases
Explanation:
The attraction between atoms in different molecules in a solid is very strong due to strong intermolecular forces present in a solid. However, such intermolecular forces are weaker in liquids than in solids.
This implies that the solid has higher intermolecular forces of attraction compared to gases and liquids. Based on the negligible degree of intermolecular forces between them, a gas has the weakest intermolecular forces hence the atom has very minimal interaction between them.