A change" is an event that some cell's content is over- written by a dierent symbol. Notice that, if initially a cell is empty, a change" occurs when it holds a non-null symbol. Turing machine M is 10- change if during any computation of M on any input word, there are at most 10 changes. (1)What is the smallest class of languages that 10-change Turing machines can accept? Prove your answer. (2) A Turing machine M is 10-change-per-cell if during any computation of M on any input word, there are at most 10 changes occurring at each cell. Prove that any deterministic Turing machine can be simulated by a 10-change-per-cell one.