Final answer:
Epidemiology is the branch of medical science that studies disease in human populations. It focuses on patterns, causes, and effects of diseases and helps shape health policy decisions and medical practice. Epidemiologists collect data, track disease spread, and investigate causes and transmission.
Step-by-step explanation:
Epidemiology is the branch of medical science that is concerned with the study of disease as it affects a community of people. It focuses on the patterns, causes, and effects of diseases in human populations, shaping health policy decisions and medical practice by identifying risk factors for disease and targets for preventive healthcare. Epidemiologists collect data about diseases, track their spread, and investigate their causes and transmission.