حیاتی ردعمل
Biological reaction, biochemical response, physiological response, a reaction or response that occurs within a living organism. This noun phrase refers to any response, reaction, or change that occurs in a living organism as a result of a stimulus. حیاتی (hayati) means biological, vital, or relating to life (from حیات, hayaat, life). ردعمل (radd e amal) means reaction, response, or counteraction (from رد, radd, rejection/return, and عمل, amal, action). Together, they mean "biological reaction." The phrase is used in biology, in medicine, in biochemistry, in physiology, and in scientific discussions of how living organisms respond to stimuli (internal or external). It has a neutral polarity. A biological reaction can be positive (healing) or negative (allergic reaction). The opposite would be "عدم ردعمل" (adam e radd e amal, lack of reaction). The phrase is formal.