Translation:That passage is very long.
It's actually closer to "sentence". As in, "An essay is composed of sentences." But still vague.
This is actually a real trouble spot for Japanese learners of English (as I've witnessed at my own schools). So, I suspect that most of their words are relative (if a sakubun has 5 danraku made up of bunshou, then bunshou are sentences and sakubun is an essay. But if the bunshou is long, we could be talking about anything from a sentence to a several-paragraph passage in a textbook). Contrastly, the English ones are specific (sometimes even to the level of the content: a passage is not an essay, but a composition could be), grammatically defined, and absolute.
"Passage" is extremely common in my English classroom. The teacher always hands out short stories, and refers to one as "the passage." We also keep on saying "In paragraph X of the passage, it said [...]" when quoting.
However, if you walk up to me on the street and say "passage," I would think you were talking about a tunnel.
After reading carefully all the comments, I think that Duolingo is teaching us how to use 文章 depending on the context. If it is long, it is a passage, but if it is short enough, it is a sentence. These words are relative to the actual text length, so they have no fixed translation.