T cells and B cells differ in the form of the antigen they recognize, and this affects which antigens they can detect. B cells bind to antigen on invaders that are found in circulation outside the cells of the body, while T cells detect only invaders that have somehow entered the cells of the body.
ABS, DWV, Solid or Cell Core sewer pipe. The solid pipe is composed of ABS at 99% while the cell core is composed of a cellular foam between 2 layers of ABS which makes the cell core pipe lighter.
Flexiable pipe is ribbed copper with a plastic like cover inside and usualy outside,with threaded fittings on each end from the factory. Flexiable can be used only between wall or floor and appliance,stove,heater,furnace, never from room to to room,through a wall or outdoors.