What is the study of all aspects of disease in the body called?

The study of all aspects of disease in the body is known as pathology. This discipline involves the examination of tissues, organs, bodily fluids, and autopsies to understand the causes and effects of various diseases. Pathologists determine the underlying mechanisms of diseases, provide diagnoses based on laboratory results, and may also contribute to the development of treatment strategies. This comprehensive approach encompasses the biochemical, physiological, and morphological changes that occur in the body due to disease processes.

The other fields mentioned, such as histology, physiology, and immunology, focus on specific areas of biology and health. Histology deals with the microscopic structure of tissues, physiology studies the functions of living systems, and immunology is concerned with the immune system and its response to pathogens. While all these fields are important for comprehending health and disease, pathology uniquely addresses the overall study of diseases, making it the most fitting choice for this question.