Answer:
The citizens of the World State are cemented when they die this allows them to be used as a source of phosphorus for the plant as fertilizers.
It produces a kilo or half( phosphorous) per person of an adult corpse.
Henry spoke that " It fine if we can go on being socially useful even after if we are dead by making the plants grow".
In this way the body was used as a fertilizer for plants in World State.