The property of a body to remain at rest or to continue in uniform motion in a straight line is called

The property being described here is called "inertia." In simple terms, it means that an object will keep doing whatever it's already doing (whether that's sitting still, or moving at a constant speed in a straight line) unless a force acts on it to change that state. For example, if you're sitting in a chair, you won't start moving on your own - it takes a force (like someone pushing you) to get you moving. And once you're moving, you'll keep moving at the same speed and direction unless another force (like friction or air resistance) slows you down or changes your direction. This idea of inertia is one of the fundamental principles of physics, and it's closely related to the concept of momentum (which describes how hard it is to stop a moving object) and energy (which is related to how much work is required to change the motion of an object). However, for this particular question, the correct answer is "inertia."