What defines a mixture? a. it cannot be broken down into simpler substances. b. it can be described by a single chemical formula. c. it can be created through a chemical reaction. d. it can be broken down into its basic substances through physical means.

allowed for the prediction of the properties of missing elements.

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.