Behavior: "the way in which an animal or person acts in response to a particular situation or stimulus"
Eating is a behavior.
Sleeping is a behavior.
Crying is a behavior.
Anxiety is more like a reaction to stress than a behavior that we <em>need</em> to do. I mean, you could say anxiety is a behavior but it is mostly classified as a characteristic or trait instead. You could respond to taking a math test be showing anxiety. But you could also be reacting to the announcment that your teacher might've made.
Transaction can be done if the security is exempted from registration in State X and transaction can also be done if the security is listed on the national securities exchange in the United States.