Is it possible that the narrator in "the raven" has dreamed or imagined his encounter with the raven? use evidence from the poem to support your response

It’s easy to doubt whether the raven is real. At the beginning of the poem, the speaker informs readers about his sleepy state:

. . .while I pondered weak and weary,

Over many a quaint and curious volume of forgotten lore—

While I nodded, nearly napping. . .

He could have easily fallen asleep while reading in his chamber and dreamt about the raven, or he possibly had a hallucination about the bird in his depressed state. The speaker is tormented by the loss of Lenore, which leads to questions about his mental stability. Also, the raven’s well-timed ability to say “nevermore” seems unreal. Even if a bird learns to parrot a word, it is highly unlikely that the bird would comprehend what the speaker is asking and respond to the speaker’s questions.  

The speaker’s description of the angels that visit his chamber and the smell of perfume also suggest that he could be hallucinating:

Then, methought, the air grew denser, perfumed from an unseen censer

Swung by Seraphim whose foot-falls tinkled on the tufted floor.

Therefore, it is quite likely that the speaker dreamt about or had a hallucination of the entire interaction between himself and the raven, and the raven was in fact not real.

the unsaturated fatty acid is a fat consist of one or more double bond in the fatty acid chain. if it contains one double bond then called as monounsaturated fatty acid however if, it contains more than one bonds called as a polyunsaturated fatty acid. true fatty acids are called unsaturated fatty acids as it reduces the risk of high blood cholesterol and good for health.