The most likely purpose of including this in the last paragraph is to

Established a sense of patriotism and support for the war.

can you be more do you have options/ if so, you can put it in the chat or edit your question (

well, i hope this at least : ) :

noun: a temporary state of mind or feeling.

adjective: (especially of music) inducing or suggestive of a particular feeling or state of mind.

examples:

hope this ! : )

the purpose of the heading in the passage is to identify who is telling the story.

this excerpt is part of the book sugar changed the world (2010) written by marc aronson and marina budhos. as the book has been written by two people, the heading "marc" indicates that this specific excerpt is being narrated by aronson. in the fragment, marc describes his grandfather's story after hearing it from his cousin. however, there are other excerpts where budhos is the one that tells the story of her family.

aronson and budhos, who are husband and wife in real life, decided to write sugar changed the world when they found out how sugar, which had an important role in slavery and economy, changed their ancestors' lives.