Which factor most likely affects viscosity of a liquid?

The viscosity of a liquid is primarily influenced by temperature due to the behavior of molecules within the liquid. As temperature increases, the energy of the molecules also increases, causing them to move more rapidly and reducing the intermolecular forces that contribute to viscosity. This results in a thinner, less viscous liquid. Conversely, when the temperature decreases, the movement of molecules slows down, and the liquid becomes thicker or more viscous.

Temperature is a significant factor that can change the flow characteristics of liquids, making it easier to manage in applications like driving and aerial operations, where viscosity can affect fluid dynamics and the performance of equipment.

Other factors such as elevation, nozzle pressure, and humidity do have some effects on liquid flow and performance but do not directly affect viscosity in the same fundamental way that temperature does. Therefore, temperature is the key factor influencing the viscosity of a liquid.