When julia wang quoted former u.s. social security commissioner dorcas hardy in her speech on reforming the social security system, she was using what your textbook calls __________ testimony?

Respuesta :

in this case, she was using what your textbook calls EXPERT TESTIMONY

Expert testimony is a testimony that came from someone that has a credential in that specific field.
Example of expert testimony: 
social security commissioner giving testimony about social security system, astrophysicist giving testimony about planet's orbital condition, Bill Gates giving testimony about the condition of software market, etc.