<prompt> Peripheral resistance is inversely propoional to:Radius of the vesselViscosity of bloodLength of the vesselElasticity of the vessel wall  <response>: Poiseuille-Hagen equation: for the flow of a fluid in a rigid cylindrical tube Q P x pr48el Q flow, P or P1 - P2 pressure difference between two points, r radius of the tube, e viscosity of the fluid, and l length of the tube. By Ohms law: Q PR; OR R PQ. R resistance Thus, viscous resistance R can be given by combining the above two formula: R 8elpr4 Thus, viscous resistance is propoional to the viscosity e of the fluid and the length l of the tube. inversely propoional to the fouh power of the radius of the tube blood vessel. Thus option A is correct. 