What is the definition of disease? How are diseases caused?

A disorder of structure or function in a human, animal, or plant, especially one that produces specific symptoms or that affects a specific location and is not simply a direct result of physical injury. Causes: Infectious diseases can be caused by: Bacteria. These one-cell organisms are responsible

A pathological condition of a body part, an organ, or a system resulting from various causes, such as infection, genetic defect, or environmental stress, and characterized by an identifiable group of signs or symptoms. Dis- ease itself explains that any discomfort related to the physical,mental or