In accordance with Le Chatelier's Principle, reactions shift away from stressors. For example, see the following equilibrium reaction. There are three distinct species: CO, H2 and CH3OH.
In organismal biology, a stressor is an external state change (such as a change of temperature or salinity) that results in a physiological response from an organism required to maintain homeostasis. Many organismal traits are occult until revealed by observing responses to stressors; this is particularly true of microorganisms.
In the field of environmental science and global environmental change there is concern about multiple stressors that impact on people's livelihoods. Climate change may be an important factor in increasing people's vulnerability but it is the combination of a change in climate with other stressors (such as changing pressure from land degradation, recurrent experiences, such as drought, and sudden shocks, such as floods and landslides) that will determine how the stressor can be coped with. The impact of these stressors create multiple stresses that are specific to the agent or system.
An event or context that elevates adrenaline and triggers the stress response because it throws the body out of balance and forces it to respond; for example:
A stressor can also be an event that provokes stress.