It didn't take "Animalia ab monte descendunt". Is it wrong?
"ab" is used before words starting with a vowel. With that said, I still don't know if "Animalia a monte descendunt" is correct. In fact I was hoping to find a discussion on the topic here. :)
A quick Google seems to tell me that "de" has a meaner closer to "down from" (apparently including in the sense of being a descendant of a family). But apparently it's also a bit more complicated than that
Not particularly sure but reporting anyway, since it's clear there is some interest in checking this. Eventually I suppose the tree will have more detailed coverage of prepositions.
Animalia de monte descendunt ac impetum faucibus in urbem faciunt.
Sed homo animal perīculōsissimus est.