A reaction by a non-human organism with behavioral and physiological elements similar to a person's response.
A person's internal state of being and involuntary physiological response to an object or a situation, based on or tied to physical state and sensory data.
A small change in a physical system, or more broadly any definable system (such as a biological or economic system)
Variation in an orbit due to the influence of external bodies
Agitation; the state of being perturbed