Primary records are more trustworthy than secondary records. The reason is because primary records were made at about the time that the recorded event actually occurred (e.g. a birth certificate or a death certificate). Additionally, primary records are recorded by persons who usually create such records (e.g. doctors or court recorders).
Secondary records are often used to provide clues for where to search for primary records. Types of secondary records include such things as family bibles, family history books, newspaper articles, etc.
Compare the types of records in the two columns below. Randomly select some of them and think about when such records would be created and who would have supplied the information for them.