The difference observed in solids, liquids and gases can be accounted for by
Answer Details
The question is asking what accounts for the observed differences in solids, liquids, and gases. The options provide four possible answers to choose from.
The correct answer is: "The spaces and forces acting between the molecules."
Solids, liquids, and gases have different physical properties because of the way their molecules are arranged and how they interact with each other. The molecules in solids are tightly packed together and vibrate in place, while the molecules in liquids and gases have more space between them and can move around more freely.
The spaces and forces between molecules determine how they behave under different conditions, such as temperature and pressure. This is why solids, liquids, and gases have different melting points and boiling points, and why they can have different densities and viscosities.