IS displayment vector quantity ?why?

Speed is a scalar quantity. ... Velocity is a vector quantity. Displacement is the difference between the initial position and the final position of a body. Displacement is a vector quantity and not a scalar quantity because it can be only described by using both magnitude as well as direction.

Liquid. good luck : )

Efficiency is an action of doing something. for example when you take a test. good efficiency means you did well but bad effeciency or no effiency means you did bad.