The primary dimensions of credibility are

A. Primary dimensions of credibility are nearly universal. 1) Expertise (competence, qualification) is one of the primary dimensions of credibility. Of the three primary dimensions, expertise usually plays the most important role. 2) Trustworthiness (character) is one of the primary dimensions of credibility. Hope that helps?

People's profiles are important because they show you who they are unless they're fake.

Generally spontaneous human combustion is something that still bewilders some, human combustion happens very rarely and doesn't affect the surrounding areas, so unless you want to set your self on fire, human combustion will remain spontaneous and very rare.