"Chicken is meat."
Translation:Kana on lihaa.
I'm guessing the logic over the use of partitive here is as follows: Kana on lihaa = (All) chicken is (one type of) meat.
The alternatives would be false:
Kanaa on lihaa = (One type/This particular) chicken is (one type of) meat. [Too specific, untrue]
Kana on liha = (All) chicken is (all) meat. [False, not all meat is chicken]
Kanaa on liha = (One type/This particular) chicken is (all) meat. [False, not all meat is a specific kind of chicken]
The subject is never in partitive when it's described with an adjective. "Kanaa on" means "there is chicken" in the sense of chicken meat.
Kanaa on paljon. = There is a lot of chicken.
Kanaa on joka ruuassa. = There is chicken in every food.
Kanaa on paistettuna ja keitettynä. = There is chicken (available) fried and cooked.
Well, in Tämä on samaa ruokaa, the subject is tämä. The partitive adjective samaa is modifying the predicate ruokaa.
And Makeaa kalaa lacks a verb, so I'm not sure if it's supposed to be a subject.
But I think a sentence like "Sweet ice cream is over there" would be Tuolla on makeaa jäätelöä, with a partitive adjective modifying a partitive subject.
But in that sentence, the adjective precedes the noun, in the attributive position.
Perhaps MikaLaari1 is talking about partitive subjects with adjectives in the predicative position, separated from the noun by the verb?
Though paistettuna and keitettynä are participles, a type of adjective, in the predicative position. However, they're in the essive case, not the nominative case or partitive case.