The brain waves associated with rem sleep are most similar to those of

The Brain waves associated with REM sleep are most similar to those of stage 1 sleep. 
The first Rapid Eye Movement sleep stage lasts around 10 minutes and usually happens after having asleep at least 90 minutes. At this stage the eye moves rapidly in all directions during Rapid Eye Movement sleep. Additionally during this stage powerful dreams usually happen.

Answer : romans built laws to manage the pollution which was lead by smoke produced by the factories.

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.