In laminar now, fluid particles are constrained to motion in (parallel - perpendicular opposite) paths by the action of (temperature - viscosity - pressure).

parallel; Viscosity

Explanation:

Laminar is flow is the flow of fluid layer in which motion of the liquid particle is very slow and there is no intermixing of the layer of fluid takes place.

There no perpendicular movement of particles takes place, no eddies are formed or swirl of fluid.

so, the first option will be Parallel. Fluid particles flow parallel to each other in laminar flow.

This path of flow is by the action of Viscosity of the fluid.