Answer:
the total amount of matter
Step-by-step explanation:
In a closed system, the total amount of matter remains the same as it is transferred between organisms and the physical environment, even though its location or form changes.
When one organism consumes another, this matter can change form, but it does not disappear. Eventually, the matter is broken down by decomposers and deposited in the ecosystem's soil, where it can be used by plants. From there, it is able to begin the cycle all over again.