"Mom does everything and dad does nothing."
Translation:אמא עושָה הכל ואבא לא עושֶה כלום.
It's a really good question. It's functioning adverbially. If it was understood as functioning as a direct object noun it would need את, as is the case in classical Hebrew at Eccl 3:11; 1 Kgs 14:26 etc. Classical Hebrew would likely have את here. But modern Hebrew prefers to treat it adverbially, as in אני אוכל הכל, "I eat everything."
You can take a Memrise course for the nikkud... or I like the JBS/Shalom TV course - JBS Hebrew: (I think vowels is lesson 2, but I can't remember). https://www.youtube.com/playlist?list=PLFYVdHvwACGu0b-foW7PDLuMfFAb6dUPV
there is also http://www.cartoonhebrew.com
Not sure why it would be לא...הכל when that would translate to "not everything" הוא לא עושה הכל - he doesn't do everything. That's something completely different. כלום on the other things means specifically "nothing" הוא לא עושה כלום - he doesn't do anything / he does nothing.
Diana, If the nikud are too small then you can zoom in by adjusting your device's settings. It depends on what device you are using. On a desktop, if you are using a web browser you can just zoom in on the screen. If you are using a smart device you can go into your settings. In Android, it's in accessibility, I have it set that if I triple tap on the screen it zooms in that area. If you can't figure out what to do, just let me know how you are accessing duolingo (a phone, tablet, computer, etc. And what type of device it is, a iPad, Android, MacBook, etc.) If you are using a web browser, also list which one.
The nikud are small in general, but in this question it's easy to know what they are going to be, ima = mom, so עושה would have to female = osa, and dad is male so it would have to be ose. This won't always help in future sentences, but in this one it will.
It's a great question. Classical Hebrew likes the negative לא next to the verb (just commenting on לא, leaving aside other negators). Preferring the negative marker next to the verb is the case with some languages but not others. Spanish likes the negative "no" next to the verb. Ya no vive aquí, "he doesn't live here anymore," but not No ya vive aquí. Having said that, Spanish can have the negative separated from the verb, as in no las traje, "I didn't bring them." And so, we can only speak of tendencies, have to allow for variation esp. in poetry, among other complications. For more, see the article by Jacobus A. Naudé, "Negation: Pre-Modern Hebrew" in Encyclopedia of Hebrew Language and Linguistics 2.801-811. He has two paragraphs on word order on pp. 804-805. That article is followed by an article on negation in modern Hebrew.