A student adds 10 drops of a copper sulfate and sodium hydroxide solution to a test tube containing egg whites. The solution undergoes a color change from blue to purple. Which organic molecule is indicated by the color change of the solution?

protein

nucleotide

lipid

complex carbohydrate

bc blah

explanation:

bc blah

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.