"I take care of the animals."
Translation:Starám se o zvířata.
I believe that the translation should be "starám se o ta zvířata", because of the "the". "Starám se o zvířata" should be "I take care of animals"
Not necesarily if the animals are already known and within the present context.
I believe there is no such word as "jse" in Czech. Not on its own. As a part of another word, such as "jsem" and "sem", the version where the beginning "j" is ommitted is colloquial. But either way, "jse" doesn't exist, at least to my knowledge.