Ecology - A branch of science that deals with the relation of organisms to one another and their physical environment.⏎
Epidemic - An often sudden increase in the level of disease in a specific population over a given period of time.⏎
Cytokine - A type of protein secreted by cells in the immune system that carries signals that facilitate cell-to-cell communication and help regulate the way the immune system responds to inflammation and infection.⏎
Gastrointestinal Tract - The structure in the body, beginning with the mouth and extending to the anus, through which food is ingested, broken down, and absorbed to provide the body with nutrients, and waste products are excreted.⏎