Health is defined by the World Health Organization as a state of complete physical, mental and social well being. Disease is any change which impairs the function of an individual in some way. These terms are difficult to define because there are so many components which can contribute to health, and these definitions are very subjective.

! outline how the function of genes, mitosis, cell differentiation and specialisation assist in the maintenance of health:

Cells are the basic structural unit of life. The genetic material in cells is responsible for the metabolic processes essential for life. A malfunction of the genetic material leads to a fault in metabolism and could harm the cells and the individual. For cells to be healthy they need an accurate copy of the genetic code, which is obtained by mitosis. Mitosis is cell division of somatic cells which produces...