Answer:
1. Allusion
2. it sets up a contrast
Step-by-step explanation:
The allusion is a figure of speech that allows a writer to make a reference to something, someone, period, history, event and anything else. We can see an example of this in the stanza shown above, when the poem makes reference to Selma and Saigon.
This figure of speech was used to promote the contrast between the violence suffered in Selva and the serenity of the photo that the poet loves.