If a chemical was placed in the water that caused all of the mosquito larvae to die, what would be one possible change in the food chain?

a). the number of algae would decrease.

b). the number of pike would increase.

c). the fisherman would catch less pike.

d). the number of dragonfly larvae would increase.

d we did this already

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.