Question

what is the primary reason the author includes the footnote at the end of the article?
to help readers verify the facts that are presented
to help readers understand a technical term used in the article
to help readers compile a list of reliable sources for information on u.s. national parks
to help readers calculate the amount of lava ejected in the prehistoric yellowstone eruption

Explanation:

Footnotes in articles often serve to provide additional context or verification for facts presented. The first option, "to help readers verify the facts that are presented", aligns with the typical purpose of a footnote (citing sources or giving details to confirm information). The other options are less likely: understanding a technical term is usually done via a glossary or in - text definition, compiling source lists is not a primary footnote function, and calculating lava amounts would involve specific data/equations not typically in a footnote.

Answer:

A. to help readers verify the facts that are presented