Molecular forces determine liquid properties

Steps:

• Recall that liquids maintain volume due to strong intermolecular forces keeping molecules close together.
• Note that lack of fixed shape results from molecules sliding past each other despite these forces.
• Compare options: identify which describe strong forces with mobility for liquids.
• Eliminate options implying weak forces (gases) or immobility (solids).

Why A is correct:

• In liquids, strong intermolecular attractions (large forces) ensure fixed volume by limiting expansion, while molecules' freedom to move allows shape change, per kinetic molecular theory.

Why the others are wrong:

• B: Fixed positions describe solids, not liquids' fluidity.
• C: Small forces lead to no fixed volume, like gases.
• D: Combines weak forces and immobility, which fits neither liquids nor other states.

Final answer: A