Which mineral scratches dolomite and is scratched by olivine?
1.galena
2.quartz
3.potassium feldspar
4.muscovite mica
10

Option (3)

Explanation:

The above-given question is based on the Mohr's hardness scale, which shows the hardness of the minerals ranging from 1 to 10, where the mineral with hardness 1 is Talc which is a soft mineral, and 10 is Diamond which is the hardest of all the minerals.

So from the above data, we can conclude that Potassium feldspar is the mineral which can scratch the surface of a Dolomite mineral and is scratched by Olivine, because its hardness (6-6.5) is more than Dolomite (3.5-4) but lesser than that of Olivine (6.5-7).

Thus, the correct answer is option (3).

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.