Which of the following groups of microbes are all heterotrophs?

Fungi are classified as heterotrophs because they obtain their nutrients by absorbing organic compounds from their environment, which they typically derive from the breakdown of dead organic matter or living hosts. This characteristic is fundamental to their role in ecosystems, where they act as decomposers, helping to recycle nutrients back into the soil. They lack the capability of photosynthesis, which further emphasizes their reliance on heterotrophic nutrition.

In contrast, bacteria represent a diverse group that includes both autotrophic (organisms that can produce their own food, like cyanobacteria) and heterotrophic species. Similarly, protozoa are primarily heterotrophic, but some are classified as mixotrophs, meaning they can utilize both organic and inorganic materials under different conditions. Algae are primarily autotrophic, using photosynthesis to produce energy, although some can exhibit heterotrophic characteristics under specific circumstances.

Therefore, fungi stand out as a distinct group of microbes that are exclusively heterotrophic, highlighting their unique mode of nutrition compared to the other groups listed.