A disease is any condition which results in the disorder of a structure or function in a living organism that is not due to any external injury. The study of disease is called pathology, which includes the study of cause. Disease is often construed as a medical condition associated with specific symptoms and signs. It may be caused by external factors such as pathogens or by internal dysfunctions, particularly of the immune system, such as an immunodeficiency, or by a hypersensitivity, including allergies and autoimmunity.
To EU-funded Earth scientists it is evident that many parts of the Earth's crust have been extracted from the underlying mantle. However, the timing of new crust formation and recycling of old crust has proven to be an elusive issue.