Which of the following organisms is known to utilize photosynthesis?

Cyanobacteria are a group of bacteria that obtain their energy through photosynthesis, similar to plants. They contain chlorophyll and other pigments that allow them to capture light energy from the sun, converting it into chemical energy while releasing oxygen as a byproduct. This process is crucial not only for the cyanobacteria themselves but also for the environment, as it contributes to the oxygen supply in aquatic ecosystems and has played a significant role in the evolution of life on Earth.

The other organisms listed do not carry out photosynthesis. Obligate anaerobes, for example, thrive in environments devoid of oxygen and typically utilize fermentation or other anaerobic processes for energy. Archaebacteria, while they can be involved in various metabolic processes, do not perform photosynthesis. Fungi are heterotrophic organisms that absorb nutrients from their environment and do not have the capability for photosynthesis, as they lack the necessary pigments and structures associated with that process.