"You try different foods."
Translation:Usted prueba comidas diferentes.
Tratar is also to try, so Tratas comidas diferentes should also be accepted.
I believe "tratar" by itself means "to treat." It means "to try" only if followed by the proposition "de."
Usted prueba comidas diferentes. it this a command or just statement. In English sentence, there is no indication to show if it is a command. and spanish answer did not give any astonishment mark, !, so that not sure what it is. so why tú pruebas comidas diferentes was marked wrong? If it were command, a pruebe should have been used, shouldn´t it?
how is usted prueba the subjunctive? Usted prueba is the formal present indicative. The present subjunctive form of probar is pruebes for tú or pruebe for usted/él/ella.