Concept:Secondary sources are materials that summarize, interpret, or compile information from primary sources. They are not original firsthand accounts.
Explanation:Information sources are divided into documentary and non-documentary types. Documentary sources are further classified as primary, secondary, or tertiary.
Secondary sources depend on primary sources for their content. They organize and present information in a structured way, such as in reference books or textbooks.
Common examples of secondary sources include textbooks, dictionaries, encyclopaedias, biographies, dissertations, indexing services, and review articles.
In contrast, letters, diaries, photographs, artefacts, interviews, oral histories, and audio/video recordings of life events are primary sources because they are original records of events.
Answer:D. textbooks, dictionaries and encyclopaedias, biographies and dissertations etc.