The particles of a liquid are able to move around each other. What property of a liquid does this behavior create?

Behaviour is in the form of surface tension.

Explanation:

The particles of the liquid are quite close to each other and move with the random movement around the containers. These particles tend to move rapidly in all directions due to the shorter distances between particles. The property of the liquids to flow is their viscosity. Described as the quality of the liquid to flow. They have no fixed shape, as they are made by tiny vibrating particles that are held together by intermolecular bonds. liquids don't disperse like the gases they have surface tension.

If the water vapor content stays the same and the temperature drops, then the relative humidity increases. its vise versa.if the water vapor content stats the same and the temperature rises, the relative humidity decreases. so, yes, i'd say that temperature and humidity have a strong relationship.