Answer:
investigating primary sources.
This means that Angelica has to carry out her research with documents that relates directly to the subject.
Explanation:
Primary sources are documents that directly relates with the subject under investigation or research, those documents could serve as evidence or information of great importance and benefit.
Primary source helps researchers, historians, artists etc to get first hand knowledge about what transpired during a time or dispensation or an historian event.
Examples of primary source includes pictures, maps, cameras, clinical reports, journals, articles, music, case studies, manuscripts, interviews, letters, phones, computers, poems, records, books, novels, videos, newspaper, etc.