For "breast" in breast of duck, the exercise uses "magret". Can you explain why? LaRousse defines "magret" as "Fillet of duck fattened for the production of foie gras.", which does not seem to be the same thing, as clearly not all ducks are forced fed to make foie gras; and clearly it would be redundant to say «de canard»
I used blanc, which seems a lot closer: «Partie charnue d'une volaille qui tient à la carcasse.» but is not accepted.
https://www.larousse.fr/dictionnaires/francais/magret/48627
https://www.larousse.fr/dictionnaires/francais/blanc/9729