Which literary device is used in these lines from the first stanza: beneath a skin, the city stretches, each street pulses? in the poem Night Flight?

Personification.

Explanation:

"each street pulses." and "beneath a skin" suggest the street has a pulse beneath a skin, which we know is not something a street has, but humans do. Personification is when a non-human thing is describes to have the characteristics or aspects that humans have. Which is exactly what the poem is doing, leaving us with the conclusion that the literary device used is Personification.

i think the answer would mist likely be an adjective clause, because unhappy is an adjective.