Answer:
Through Mutation
Explanation:
Since our cells are able to produce exact copies of themselves. Thus, until unless some mutation has occurred and affected the ability of the cells to produce exactly similar duplicates copies of the parent cell, there is no way that an individual gets aged.
Since, mutation affects the mitochondrial DNA it is pretty sure that a mutated cell has affected the longevity of a normal cell and then that mutated cell has produced million other mutated aged cell by replicating itself
The opening and closing of ligan-gated ion channels
b i gotta write 20 words thats bs but i think its b