What scientific field primarily studies the impact of protozoa?

The scientific field that primarily studies the impact of protozoa is microbiology. Microbiology encompasses the study of various microorganisms, including bacteria, fungi, viruses, and protozoa. Protozoa are unicellular eukaryotic organisms that can have significant effects on ecosystems, human health, and diseases. In microbiology, researchers examine the biological characteristics, life cycles, ecology, and pathogenicity of protozoa, which contributes to our understanding of their roles in various environments and their interactions with other organisms.

In contrast, botany focuses on plants, entomology is the study of insects, and virology deals with viruses. While these fields may touch upon aspects of protozoa indirectly, they do not primarily focus on the impact and study of these organisms as microbiology does. This makes microbiology the correct choice for understanding protozoa and their effects.