Final answer:
A) Decomposers and D) detritivores are responsible for breaking down consumer waste and dead organic matter, with decomposers using chemical means and detritivores using physical digestion.
Step-by-step explanation:
Consumer waste and dead organic matter are broken down by decomposers and detritivores. Decomposers, such as bacteria and fungi, chemically break down waste and dead organisms into simpler inorganic molecules, releasing nutrients like carbon and nitrogen back into the ecosystem for use by producers. While decomposers perform this process chemically, detritivores physically ingest and digest organic matter, often contributing to this decomposition process.