Under the conditions given, "to" is a preposition.
The part of speech for "answer" is a noun.
The part of speech for "archaeologist" is a noun.
Permission is a noun.
Ethics code is a noun. It is rules of code which must be followed in order to be ethically correct.
Touchdown is a noun.
The part of speech for the word diplomacy is a noun.
Ethics code is a noun. It is rules of code which must be followed in order to be ethically correct.
A noun, specifically a proper noun.
The word speech is a noun.
There is only one part of speech in a noun--noun.
Noun
The part of speech for "lecturer" is a noun.