What reaction occurs when calcium carbonate is treated (separately) with (i) nitric acid, and (ii) sulfuric acid?
Each acid liberates carbon dioxide............
So we would see fizzing (i.e. the evolution of the gas), and the dissolution of solid carbonate. Calcium nitrate is soluble.
Again the gas would be liberated, but calcium sulfate is only very moderately soluble in aqueous media. I would expect to see the solid salt to go up, and then reprecipitate as the sulfate.
Nothing of what I write here is a substitute for actually doing the experiment in a laboratory, and observing and recording the results.