Which blood cell transport oxygenated blood

The arteries transport oxygenated blood.

In terms of cell the red blood cells or the RBCs transport oxygenated blood

a time line cause it goes from 685 to 978

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.