(2009? Qingyuan) Tofu is an important invention in ancient China, while Qingyuan's Jiulong Tofu is flavored with local unique ground beans.

(1) From the label, tofu contains protein, sugar, oil, water and vitamins.

(2) According to the nutritional elements contained in food, we can know that foods containing protein are: fish and bean products;

(3) In the process of making tofu, beating is a physical change, and tofu flower is separated from water by filtration;

(4) According to the meaning of the question, calcium oxalate is solid, so the chemical equation of the reaction between sodium oxalate (Na2CO4) solution and calcium sulfate can be written: Na2CO4+CaSO4 ═ Ca2O3 ↓+Na2SO4.

So the answer is: (1) vitamins? (2)B？ (3) Physical filtration? (4)Na2C2O4+CaSO4═CaC2O4↓+Na2SO4