Final answer:
Boldfaced headings in a text are typically used to denote subtopics within that text. They structure content and are not usually used for citations, author's opinions, or glossary entries.
Step-by-step explanation:
The boldfaced headings in a text most likely correspond to subtopics within the text. These headings serve to organize content and make it easier for readers to follow the structure of the document. Sub-headings may also guide you towards different sections like end-of-chapter summaries, review questions, and a glossary, instead of citations and references, which are typically not boldfaced. Author's personal opinions and glossary terms themselves would not usually be the main headings but could be highlighted or explained within those sections.