Read the passage carefully and answer the questions that follows.
Developments in electronic science have transformed the art of record keeping in the modern age. Traditionally, records of events were kept only in peoples mind. It depended very much on the retentive power of the human memory. This was extremely dangerous as people either forgot events wholly or in parts, or deliberately falsified details to suit their various interests. Interminable arguments were thus the order of the day.
Even writing which replaced mental recording was not entirely free from these shortcomings as untruths could be written as true records either willingly orinadvertently. With the advent of electronic memory, however, these dangers now show not only what happened, but also who did or said what, including how and when.
How many stages of development did the writer mention while discussing the art of record keeping?
