Which item is an example of a secondary source

An advantage of primary over secondary sources for any historian would be that they reveal how individuals experienced certain historical events as they were unfolding - this tells us how they actually reacted to the event and not the later revision of their reactions.

cherokee and arikara

the  seven  days  battles  were  a series of seven battles over seven  days from june 25 to july 1, 1862, near richmond, virginia,  during  the american civil war. the  seven  days ended with mcclellan's army in relative safety next to the james river, having suffered almost 16,000 casualtiesduring  the retreat.