This simply means that atoms or elementary particles building up atoms, do not disappear, nor are they newly produced anywhere. Prosperity and life itself depend on whether matter is concentrated and structured, or whether it is dispersed and mixed, that is, in chaos. If matter on earth is systematically concentrated and structured into ordered matter, that is the fundamental principle of prosperity and health. If we disperse it and consume its quality into chaos, that is the basis of death and poverty. Due to the laws of thermodynamics, which we have known since the 19th century, it is impossible to maintain quality in any closed system if it is completely closed.
Any closed system is doomed.
The end stage is complete chaos of matter. This process is only stopped by energy coming in from outside the system. In the case of Earth, that is done by the sun, energizing green cells, systematically concentrating and structuring matter into net quality. It's the same for car manufacturing, and other processes that are not fueled directly or indirectly by the sun. So maintained prosperity and health rest on the fact that we must not dissolve more matter into dispersed waste than is reconstituted back into the ordered forms again.