Which of the following is considered a primary source of data?

A primary source of data is an original, firsthand account or evidence directly related to the topic or research question being investigated. This type of source presents information that has not been altered or interpreted by others.

Collecting data sets from experiments represents a clear example of a primary source because it involves direct observation or measurement of phenomena. This data is the result of original research, capturing raw information at the time of study, which can later be analyzed or interpreted by others but remains a fundamental building block for scientific inquiry.

In contrast, a biography of a scientist, an academic journal article, and a review of previous studies are secondary or tertiary sources. They summarize, interpret, or analyze information already established by primary sources, lacking the direct first-hand evidence that characterizes primary data.