I figured I would add to this. It is very much treated like pants would be, and several other uncountable nouns. The only difference between Danish and English is that when using the definite article or form, then it declined according to the number, which it isn't in English. For instance: the pants = bukserne (pants = bukser), and when adding an adjective it becomes the purple pants = de lilla bukser, since the definite article is moved in front of the adjective describing the noun.
no, because "de" provides the definite here together with the preceeding adjective. You can ask "er risen lys? (is the rice light/bright?) or you can say "Jeg har risen (I have the rice, where 'en' serves as 'the' on the end for masculine noun)" or you can say "jeg vil have de lyse ris" ( I will have the light/bright rice. You can't use both 'de' and 'en' together, you would be saying 'the bright the rice') Also, rice doesn't change form between singular and plural forms, kind of like in English, one grain of rice or a bowl of rice. That was all a bit mixed up, but I hope you can see the pattern in it all...
I think duo likes to give us sentences that don't make sense in the real world to test us on usage outside of contextual clues. Like with our black strawberry and animals doing human things. If they used rødt jordbær, we could assume what color it is from just knowing strawberries are red. I admit to have gotten caught out making assumptions like this many times.