The combined effects of inherited factors (nature) and environmental factors (nurture) on the development of an organism. Traits that are determined by numerous genes (see quantitative inheritance), such as height in humans, tend also to be subject to environmental factors, such as nutrition in this example, i.e. both genes and environment direct the eventual phenotype, which can show considerable variation. Hence, the genetic potential of an organism will only be realized under appropriate environmental conditions. See also phenotype.