Which type of scientific statement is defined as a hypothesis or group of hypotheses that can be accepted as true based on repeated experimentation with similar results?

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.

its probably to later but whats the question