Which type of organisms are described as single-celled and capable of independent division?

The correct answer, bacterial cells, is appropriate because bacteria are indeed single-celled organisms, classified as prokaryotes. One of their defining characteristics is that they can reproduce independently via binary fission, a process that allows a single cell to divide into two identical daughter cells. This ability to reproduce independently is a fundamental aspect of their biology.

Bacterial cells are vital for various ecological processes, including nutrient cycling and as part of the microbiome in many organisms. Their independent division is crucial for survival, adaptation, and proliferation in diverse environments, which distinguishes them from other types of organisms mentioned.

In contrast, viral particles do not fulfill the criteria of being independent cells; they require a host cell to reproduce and cannot perform metabolic functions on their own. Parasitic protozoa, while also single-celled, often rely on complex life cycles or host organisms for reproduction. Fungi, on the other hand, are typically multicellular organisms (with some exceptions in single-celled fungi like yeasts) that reproduce through different mechanisms, such as spores, rather than independent cellular division like bacteria.