To locate the epicenter of an earthquake a seismologist must determine all of the following except a the difference in the arrival times in the p and s waves b seismograph data from the locations c the distance from the epicenter to three different seismograph locations d the intensity of the earthquake

true is the answer : )

they had the law tat factories that produces smoke cannot be built near residential buildings.

building of proper sewage system was done to ensure that the waste is carried away from the humans so that they do not get diseases from it.

also they built water systems to provide water in those areas which are drought prone.