What does a metaphor do in poetry?

compares two similes

compares one thing to itself

compares two things that seem to be unlike each other

compares one form of diction to another

Which persuasive technique is used in the passage below? after seeing ads for greasy french fries, sugary soft drinks, and salty chips, you head to the kitchen to fix yourself an enormous (and unhealthy) snack. with the tv blaring in the background, you then waste hours on the web.