Which of the following is NOT a true statement?* 1 point
Two or more atoms held together with bonds make up a molecule.
Mixtures can be made of two elements, two compounds or an element & a compound.
At least two different types of atoms are required to make a compound.
Pure substances are made of only one type of atom.

really dont know just need some points

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.