$A$ body is moved along a closed loop. Is the work done in moving the body necessarily zero? If not,state the condition under which work done over a closed path is always zero.

(N/A) No,the work done in moving a body along a closed loop is not necessarily zero.
Work done is only zero when the forces acting on the body are conservative forces.
$A$ conservative force is a force with the property that the total work done in moving a particle between two points is independent of the path taken.
Examples of conservative forces include gravitational force and electrostatic force.
In contrast,non-conservative forces like friction or air resistance dissipate energy,meaning the work done over a closed loop is not zero.