"These are vegetarian cheeses."
Translation:אלה גבינות צמחוניות.
From the Tips and Notes:
The same applies to "these" and "those": both are covered by a single word. In the plural, masculine and feminine words both use "אלה" (ele). We also teach the word אלו, which in Modern Hebrew has exactly the same meaning, although it is less common and slightly higher register than the former, אלה.
In case this is helpful: The classical Hebrew form for "these" was אלה but in Mishnaic Hebrew it was אלו. So in the foundational Jewish texts of mikra in both oral and written torah, you will find both of these forms. When Hebrew was being revived as a modern spoken language for the newly founded Israel, what choice did they have but to keep both? If you read the tanakh you will find one form predominates, whereas if you read mishnah or tosefta, for instance, you will find another. I've been reading some mishnah lately, so I put אלו but I paused and had to think about it.
tips and notes are your friend: http://duolingo.wikia.com/wiki/Hebrew_Skill:Determiners
That is strange. אלה is the default answer, so that should not be happening.
Actually, as you can also see in other comments in the thread, both אלה and אלו are completely interchangeable for both genders. The difference between them is that they come from different periods, and אלו is now slightly more formal.