"The old trees are different."
Translation:Ty staré stromy jsou jiné.
The animacy distinction only impacts Czech grammar for the masculine gender. Viry (viruses, singular vir or virus) are indeed inanimate. Baktérie (same in both numbers) is feminine, but we also use the less technically accurate word bacily (bacilli, singular bacil), which is masculine inanimate. Looks like we only cross the animacy line for protozoans when we reach prvoci (singular prvok), which is masculine animate.
Do you use the masculine inanimate for feminine plural? Cause i keep seeing it being it like that. For example " jsme malé a hezké ženy " Im really confused about where and when to use which cause ive also seen the feminine singular be used for neutral plural. For example " to jsou stará zvířata? " Help
The short answer is... yes, different genders of adjectives (and nouns) can take the same endings in the same or in different cases. You just need to learn what goes where, and it likely will require some effort. This is a useful reference for a lot -- really a lot -- of declension information: https://en.wikipedia.org/wiki/Czech_declension#.
Also, without "the," the English sentence is slightly different: "Old trees are different." That refers to old trees in general, while this sentence refers to a particular group of old trees, as the inclusion of "the" indicates. For example, you might be looking at a group of trees of various types, sizes, and ages, and it's obvious that the "old" trees among them are quite different -- say, taller, wider, bumpier, and generally more impressive-looking.