After I Stated the phonetic environments in which the sounds [n] and [ŋ] appear.[from a list of words]
How should I identify natural classes of sounds that appear in the environments I’ve provided? Thank you.
You have to know the vocabulary of phonetic properties, or at least the relevant subset. If you look at the IPA chart, the descriptions of rows and columns are given, although oddly you have to work a bit harder to get "voiced" and "voiceless" from the chart. Your textbook will probably also give you a list of terms. You just check what term is constant through the list of segments in question.