Which of the following events can result in inheritable genetic variations in organisms?

translation errors during protein synthesis
genetic recombination during meiosis
mutation of DNA by environmental factors
occurrence of viable errors during DNA replication

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.