Endogeny

The word endogenous means "arising from within", the opposite of exogenous.

Biology

Endogenous substances are those that originate from within an organism, tissue, or cell [1]. Endogenous retrovirus are caused by ancient infections of germ cells in humans, mammals and other vertebrates. Their proviruses remain in the genome and are passed on to the next generation.

Endogenous processes include circadian rhythms.

In some biological systems, endogeneity refers to the recipient of DNA (usually in prokaryotes). However, due to homeostasis, discerning between internal and external influences is often difficult.

Psychology

An emotion or behaviour is endogenous if it is spontaneously generated from an individual's internal state.

Economics and finance

A variable is called endogenous if it is explained within the model in which it appears. For example, in a supply and demand model of an agricultural market, changes in the weather or in consumer tastes would be exogenous variables that might shift the supply and demand curves; the price and quantity of trade would be the endogenous variables explained by the model.
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