The type of credibility when a speaker establishes common ground with the audience

derived credibility

Derived credibility is the credibility a speaker has developed in delivering speeches.  The speaker establishes common ground with his audience, supports an argument with believable pieces of evidence, and professionally presents a well-delivered speech.   He is an  effective spokesperson because he possesses the so-called “Three C’s of Credibility.” Compassionate, Competent and Confident. 

a symbiotic relationship with the mitochondria