Is it possible for one body to be at rest and moving at the same time? Why is that?

yes

Step-by-step explanation:

it is possible that a body can be moving and at rest at the Same time. this is relative motion. an object that seem to be in motion for one subject can be stationary for another.

For example, A passenger in a bus. he/she is moving for a person walking on the pathway. but for the passenger next to him/her, they are at rest.