$A$ body falls towards the Earth in air. Will its total mechanical energy be conserved during the fall? Justify.

(N/A) No,the total mechanical energy will not be conserved.
During the fall,the body experiences an air resistive force (drag),which is a non-conservative force.
Work done against this resistive force results in the dissipation of some mechanical energy into heat.
Consequently,the gain in kinetic energy $(KE)$ is less than the loss in potential energy $(PE)$,meaning the total mechanical energy decreases over time.