Which part of the nervous system is the first to respond when Joshue feels a raindrop fall on his arm? brain
spinal cord
sensory neuron
motor neuron

sensory neuron is the first-aid part to respond.

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.