Answer:
They break apart dead organisms
Explanation:
Decomposers play an important role in the flow of energy through an ecosystem. They break apart dead organisms into simpler inorganic materials, making nutrients available to primary producers.
I would say D the Billingsella Corrugata, it IS in the oldest recorded time line, so by theory, it's the oldest (Don't quote me on that, I'm not %100)
LOW WAGE IS THE AWNSER I BELIVE