What is a hybrid tell me if you do

A hybrid is an animal or plant resulting from a cross between genetically unlike individuals,a picture is below as an example of a HYBRID

Also, a hybrid can be something changed after being created.

Hybrids can be; cars,animals and even people (nephilim).

I hope this helps

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.