The term you're looking for is "stimuli." In the context of biology, stimuli refer to changes in the internal or external environment that provoke a response from an organism. This can include a wide range of factors, such as temperature changes, light, sound, touch, chemicals, or even internal signals related to the body's physiological state.
In a broader context, in fields like organizational behavior or management, changes in the environment that necessitate a response can be referred to as "environmental factors" or "market dynamics." These terms encompass various influences that compel individuals or organizations to adapt or change their behavior or strategies.