A developer is interested in deriving an index of the difficulty of the average item for his math test. As his consultant on test development, you advise him that this index could be obtained by:_.

here is the answer to number 1: the egyptians created a 360 day calendar, and sundials to keep track of time.

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1. advanced cities

2. specializied workers

3. complex institutions

4. record keeping

5. improved technology

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answer; /// i believe that the correct answer is (fossils); //////////