How does the author introduce the theme of
unrequited, or unanswered, love?

reasoning from several particular examples to establish a general principle

"the sandy walls seemed to collapse in on themselves"

and

"the bloodshot waters seemed to have no bottom"

answer: from these honored dead we take increased devotion to that cause for which they gave the last full measure of devotion—that we here highly resolve that these dead shall not have died in vain, that this nation under god shall have a new birth of freedom, and that government of the people

explanation: