Final answer:
Root events cannot be accelerated.
Step-by-step explanation:
According to the question, only root events can be accelerated. In physics, a root event refers to an object or particle that is in its original state and not the result of any previous event. Since an acceleration can only occur when there is a change in an object's speed or direction, it is not possible to accelerate a root event as it is already in its initial state.
Therefore, the answer to the question is 1) None. No root events can be accelerated.