Duduli

The different layers of a non-equilibrium gas may have different velocities.In such a case, the layer moving faster will import momentum to the layer moving slower to bring about an equilibrium state. Thus, the transport of momentum gives rise to the phenomenon of viscosity. Viscosity is the phenomenon of transportation of momentum.

Answer:- A liquid-flow in which the different layers or laminae glide over one another at a slow and steady velocity (below its critical velocity), without intermixing, is called a laminar, streamline or Viscous flow.