Reactivity usually influence our temperament especially our responds to new or challenging environmental stimuli as well as self-regulation i.e control of our response.
In psychology, temperament can be regarded as differences in the behavior of individuals, which is not as results of learning.
It is usually biologically based , however, individuals needs self-regulation to control ones response to this.
Therefore, the correct terms that answer the question are reactivity;self-regulation.
Wait is this about the movie Coraline or is this about a historical topic because the topic you picked is social studies but my brain automatically said the movie Coraline