"A cat is an animal."
Translation:Kot jest zwierzęciem.
Essentially kot, to and zwierzeciem are all selectable in the tabs, while 'jest' is not. So when I chose "kot to zwierzeciem" from the list, I received an error which indicated that I should have selected 'jest', but 'jest is not available to me. Does that make sense or clear as mud? (difficult for me to include accents btw - hope that doesn't trip you up)
It seems that the exercises are not necessary created on the base of the 'basic sentence' (the one that was put by the course creators in the first place), but just one of the starred answers. And the starred answers are "Kot jest zwierzęciem" and "Kot to zwierzę". If you can create one of those, then everything is correct.