Activism, in a general sense, can be described as involvement in action to bring about change, be it social, political, environmental, or other change. This action is in support of or opposition to one side of a controversial argument.
There are many different forms of activism; a select list follows.
... and Vronsky are at the station to welcome Anna and Vronsky's mother respectively. This is the occasion the first meeting of Anna and Vronsky. As they, Anna and Countess ...