The process that takes place when an organism responds to a stimulus is known as a response or reaction. This usually involves a series of physiological and behavioral changes aimed at maintaining homeostasis or survival. For example, in animals, the nervous system processes sensory information, triggering muscle movement or hormonal changes that enable appropriate responses, such as fleeing from danger or seeking food. In plants, responses to stimuli can include growing towards light (phototropism) or closing stomata in response to drought. Such responses are essential for adaptation to environmental changes.