What type of microorganisms lack chlorophyll?

The chosen answer is bacteria, which is correct because bacteria are a diverse group of single-celled microorganisms that do not contain chlorophyll. This means they do not perform photosynthesis like plants and certain types of algae do. Bacteria can be found in various environments and can have various metabolic processes—some are photosynthetic and some are not, but the group as a whole lacks chlorophyll.

Fungi, while also lacking chlorophyll, pursue their growth through decomposition and absorption of nutrients from their surroundings rather than through photosynthesis. Algae, on the other hand, are primarily photosynthetic eukaryotes and contain chlorophyll, which they use to convert sunlight into energy. Viruses, while also lacking chlorophyll, are not classified as microorganisms in the way bacteria and fungi are, as they are acellular and require a host cell to replicate. Thus, bacteria is the most accurate choice when considering microorganisms that lack chlorophyll in the context provided.