How are scientific theories and laws developed? A. By using evidence from many investigations
B. By consulting the opinions of famous scientists
C. By including traditional and religious explanations
D. By throwing out unexpected evidence

airlines i think? or a cruise boat? does this work out for u? ?

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.