Question

how do single - celled decomposers get energy?
they feed on living organisms.
they use a process called budding.
they break down dead organisms.
they make their own food.

Explanation:

Decomposers, including single - celled ones, obtain energy by breaking down dead organisms. This process releases nutrients back into the ecosystem. Feeding on living organisms is characteristic of consumers (not decomposers). Budding is a form of asexual reproduction, not a way to obtain energy. Making their own food is for producers (like plants via photosynthesis), not decomposers.

Answer:

They break down dead organisms.