Noun.
It is an abstract noun.
Certainly. It is a very controversial subject in the US right now and there is lots of material to draw from. You need to decide what your point of few is. Is the speech to be informative? Or are you trying to persuade your audience that illegal immigration is good or bad?
The part of speech for this particular word is a noun.
part of speech
The part of speech for "answer" is a noun.
what part of speech is beneath
adverb
The part of speech for "explicit" is an adjective.
The part of speech for "lecturer" is a noun.
The part of speech for "rapid" is an adjective.
The part of speech of "came" is a verb.
The part of speech for "breezy" is an adjective.
The part of speech for "buried" is a verb.