It's "ja idę do domu". Well, generally the notion is not that easy to translate. We decided to go with:
iść = to be going, to be walking (right now)
chodzić = to go, to walk (generally), also sometimes 'to be walking' if there's no purpose in direction in this walking.
Theoretically, "idę do domu" means that you will walk home. But in fact, it will just be "going". By car, by train, whatever you want. You can specify that you will take some vehicle by saying "jadę do domu", but it's not really necessary.
Spadam. Spadać literally means 'to fall' (move to a lower position under the effect of gravity, as Wiktionary beautifully clarifies - what I mean, that it's not when you trip on a banana peel and fall, but when you fall from a tree or a tall building or something else)
I would compare using Spadam (stąd) to "I'm outta here" (the 'stąd' part is not necessary but means 'from here')
Oh, spadać is imperfective, that's exactly why it can be used in the present. But if you were to use it literally, that could only happen when you're actually mid-air, waiting for the painful crush with the ground ;) Or if you regularly fall from things and places.
that is a tricky question, as English go translates to different verbs, depending on transportation. But yes go can be translated to iść/chodzić. "You are going" should be accepted
But this course tries to tech you a difference between iść and chodzić. Iść is a "right now" verb, and "chodzić" is " frequently" verb so while in some context both are possible, we make you translate.
idziecie= you are walking/going
Normally, the Continous forms (to be walking, to be going) translate to "iść" and Simple forms (to walk, to go) translate to "chodzić".
"to be walking" can be also translated as "chodzić" if there is no direction and purpose, if that is just walking around.
As this is "iść" it needs a Continous form in the answer.
I put "you go" and it was marked incorrect. I put "You are going" and it was marked correct. Forms of isc was used for all verbs in this lesson, and I used forms of "going" and they were marked correct. It seems to be inconsistent not to accept "you go" while accepting all the other grammatical forms.
These are Verbs of Motion, and unlike almost all other verbs in Polish, they do show a difference between Present Continuous and Present Simple.
"iść" (Wy idziecie) is for something that is happening right now, Present Continuous. "You go" is not a translation as it's Present Simple. You would have to use "Wy chodzicie". Provided that "You go" on foot, of course.
(a lot) more info here: https://www.clozemaster.com/blog/polish-verbs-of-motion/