Question

what is the best definition of viscosity?
a liquids resistance to mix with other liquids
a liquids ability to change color
a liquids resistance to flow
a liquids resistance to change state

Explanation:

Viscosity is a measure of a fluid's internal resistance to flow. It describes how thick or thin a fluid is. For example, honey has a high viscosity (resists flow) while water has a low viscosity (flows easily).

Answer:

a liquid's resistance to flow