Concept:Viscosity is a fluid's internal resistance to flow. Honey has the highest viscosity among the given options.
Explanation:Viscosity arises from intermolecular forces and opposes the relative motion of fluid layers.
It is measured in Pascal-seconds (Pa·s). A higher value means thicker, slower-flowing fluid.
Given the typical viscosities:
Honey has a viscosity of 10 Pa·s, which is much larger than water (1.0 Pa·s), air (extremely low), and blood (3-4 Pa·s).
Therefore, honey is the most viscous substance among the options.
Answer:D. honey