The competition is open to all secondary school students, i.e. students of gimnazjum, liceum, technikum, as well as students of zasadnica szkoła zawodowa.
Yes, it is not necessary for all students in one team to attend the same school. However, they still need to be coordinated by a teacher.
Yes, one teacher can coordinate one of more teams.
This is unfortunately not possible. Each language has its own category and combining them would make the evaluation difficult. Both essay and presentation need to be written either in English, French or German.