Activism is an action which took place in an effect of social change. In other words, how to change the world.
An activist is a person whether he/she is working hard to achieve social or political change.
For example: Ric O’ Barry is an activist and director of “Dolphin Project”. He made a documentary movie “The Cove” where it focuses on Japan’s deadliest secret. That secret is where the Japanese fishermen lure the dolphins into the cove and kill them for human consumption which you will discover the meat has a high levelof mercury. The Japanese dolphin trainers select perfect dolphins for human entertainment and this leads to captivity or animal trafficking. O’ Barry published two books “Behind the Dolphin Smile” and “To Free A Dolphin”. He has a website: http://dolphinproject.org/ and http://savejapandolphins.org/
Another example: Hayden Panettiere, an actress and a hero of dolphins.