Read the dictionary definition of agent. All definitions for this word.
1. the semantic role of the animate entity that instigates or causes the happening denoted by the verb in the clause
2. an active and efficient cause; capable of producing a certain effect
1. their research uncovered new disease agents
3. a businessman who buys or sells for another in exchange for a commission
4. a representative who acts on behalf of other persons or organizations
5. any agent or representative of a federal agency or bureau
6. a substance that exerts some force or effect
