Which of the following is defined as the study of small life forms?

The study of small life forms is accurately described as microbiology. Microbiology focuses on organisms that are often not visible to the naked eye, including bacteria, viruses, fungi, and protozoa. These life forms play crucial roles in various ecosystems, human health, and biotechnology, making the field of microbiology essential for understanding complex biological processes and addressing public health issues.

In contrast, the other fields mentioned have different focuses: meteorology is the study of weather and atmospheric conditions, entomology concentrates on the study of insects specifically, and botany pertains to the study of plants. Each of these disciplines addresses different aspects of life and the environment, but they do not encompass the broad category of small life forms like microbiology does.