Which of these groups are classified as decomposers?

Bacteria and fungi are classified as decomposers because they play a crucial role in breaking down organic matter. Decomposers are organisms that feed on dead or decaying organic material, recycling nutrients back into the ecosystem. Fungi, for instance, secrete enzymes that decompose complex organic compounds, allowing them to absorb nutrients. Bacteria also contribute to this process through the breakdown of organic material, supporting nutrient cycling and soil health.

This ability distinguishes them from the other groups in the options. For example, birds and fish are primarily consumers in their ecosystems, as they typically consume living organisms or plant matter. Insects and reptiles also fall into the categories of consumers or predators rather than decomposers. Plants and algae are producers, as they generate energy through photosynthesis. Hence, fungi and bacteria are the only group listed that effectively perform the critical ecological function of decomposition.