Carbohydrates are nutrients that supply the main energy source for the body. true or false?

colors do exist. the color of the sky is actually violet; humans percieve the color of the sky as blue.

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.