He is known as an activist for environmental issues.

He is a very active person.

Action potential is an important mechanism for nerve cells to transmit information.

He is passionately engaged in extracurricular activities.

He is suspected of being involved in the sabotage of the company.

He is suspected of being involved in the sabotage of the company.

He likes watching old movies.

He is lobbying to influence politicians.

He is actively participating in social movements.

He understands the importance of learning.