Whole is less formal, a bit more common implies the wholeness of a single undivided object, not a collection of parts, not a sum of parts;not broken or damaged, intact: used with singular countable nouns, e.g.: a whole loaf of bread / a whole person / whole life (one’s life as a single unit); cannot be used with plural countable nouns or uncountable nouns.
Regularity is for Present Simple (one-word verb or one word verb+s after he, she, it) shows regular / repeated actions. Temporality is for Present Continuous (am / is / are + verb+doing shows what you are doing temporarily (in this period of life).
an ally - allies an army - armies a baby - babies a beauty - beauties a berry - berries a cherry - cherries a city - cities a cry - cries a colony - colonies a country - countries a dictionary - dictionaries a duty - duties an enemy - enemies