Question

give reason-the velocity of an object at rest is considerd to be uniform

Answer 1

A body at rest has velocity 0m/s.
If it continues to b at rest, then the velocity of the body at every second will continue to b in 0m/s.
as in each instant the velocity of the body is constant (0m/s) that is it is not changing, we can say that the body is having an uniform velocity.