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.⏎
Contagion - A general term for any disease-causing infectious agent spread by direct or indirect contact.⏎
Ecology - A branch of science that deals with the relation of organisms to one another and their physical environment.⏎
Disease - Any abnormal condition that affects all or part of an organism, resulting in symptoms such as pain or loss of function.⏎
DNA - Short for deoxyribonucleic acid, DNA is any of the nucleic acids that contain the genetic instructions necessary for the development and functioning of all living organisms as well as some viruses.⏎