This is the 930th most frequent Turkish word.
öğrencileri
"Öğrencileri" means "their students" or "the students" depending on context.
Here, 'öğrencileri' is the accusative form of 'öğrenciler' (students) indicating that it is the direct object of the verb 'kontrol etti' (checked).
Öğretmen, sınıfta öğrencileri kontrol etti.
The teacher checked the students in the classroom.
In this case, 'öğrencileri' indicates the object of the verb 'bekliyoruz' (we are waiting), concerning whom the waiting action is performed.
Bahçede öğrencileri bekliyoruz.
We are waiting for the students in the garden.
Here, 'öğrencileri' is the direct object showing which individuals were selected by the team in the context of the verb 'seçti' (selected).