A biogeochemical cycle is a pathway by which a chemical substance moves through biotic (living world) and abiotic (lithosphere, atmosphere, and hydrosphere – non-living) components of Earth. Such cyclic flow involves the transfer of matter and energy between the different components of the biosphere.
Disease refers to any condition that disturbs or modifies the normal functioning of the living organisms. Each organ system of our body has specific organs to perform particular functions. In the presence of a disease, functioning or the appearance of one or more systems of the body may change. These changes give rise to symptoms and signs of disease.