Authority is the WHO. Who is the author of the website? Val needs to check through the site thoroughly. She should be able to determine who created the site. Is it a government site with a web address (URL) ending in .gov or an educational institution site with an URL ending in .edu? The Centers for Disease Control and Prevention is part of the U.S. Department of Health and Human Services. Information from this website is considered accurate because it is backed by an authoritative source. Val found information on safety issuses related to tattooing from the CDC.
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