"The horses eat a few apples."
Translation:De paarden eten een paar appels.
It didn't mark "appelen" as incorrect. Are both appelen and appels perfectly interchangable or is there some small difference?
so based on the convention, am I correct in surmising that "appel" is a "de" noun?
Indeed! Edit: 'de' is the article for all plurals, whether it is a 'de' or 'het' noun.