"I eat them."
Translation:Ik eet ze.
You can start by going to Duo's own page on object pronouns in the Duo Tips and Notes:
For further explanations, try searching "Dutch pronouns" on Google.
No, you're not at all. The nuance with this specific word is something I learned on dutchgrammar.com. The site hasn't been updated since maybe 2012, so for adverbs, etc, there's just a very short "in progress" word doc, but what's there for sentence verbs, nouns & articles, and pronouns is really good. The way these stressed words work isn't really explained all that well by Duolingo, and I totally get it that it's not how Duo teaches. But if you want things to be shown a different way with examples next to each other, that grammar site is good and explains things in a way that make sense to me. And for this specific, they translate into English exactly the same way: "ze" and "hen" are both just "them" in English, but in Dutch they're different types of "them," and one happens to refer to people, so for this sentence, it accepted the one that means eating people. :) Or rather... :-/
That clears it up a little. I haven't been to school or learned anything for the last two decades, so trying to even remember what the heck an adverb, adjective or what prepositions and things are, well, I would have to go back and study my own language again just to learn that again! My peanut is half roasted by now. I ask my Dutch husband questions and he doesn't even know.
The correct pronoun is either "hen" or "ze". "hen" is correct only if by "them" you are referring to people. "ze" is correct for either people or things.
When you typed "hun", DL thought it was a typo for "hen". "hun" is not correct, because it is an indirect object pronoun, and you need a direct object pronoun here.
As an object pronoun, "hun" is used for the indirect object. In contrast, "hen" is used for the direct object and for the object of a preposition. Therefore:
1. Ik hab hun die informatie gegeven = I gave them the information.
2. Ik hab de informatie aan hen gegeven = I gave the information to them.
The above is the standard for university-level written Dutch. But usage of hun/hen varies regionally and colloquially.
In addition to its use as object pronoun, "hun" can also be the plural possessive pronoun -- that is, "their". However, "hen" is not used as a possessive pronoun.