Final answer:
Transcripts of speeches by historic world leaders are primary sources, which provide direct evidence from the time period of the events they describe.
Step-by-step explanation:
Transcripts of speeches delivered by powerful world leaders throughout history serve as primary sources. These are documents that provide direct evidence about a subject since they originate from the time period being studied. Primary sources include diaries, letters, speeches, and other types of documentation that were created at the time of the events in question, and they are essential for historians to develop accurate interpretations of historical events. Evaluating these sources requires an understanding of the author, audience, intent, and context.