~の中には (among, partitive)

The partitive pattern [noun]+の中には, used to single out a subset within a group — 'among X, there are (some that/who) Y.' Often paired with ~(が)ある/いる closing the construction: 学生の中にはサボる人もいる ('among students, some skip class'), 問題の中には難しいものがある ('among the questions, some are difficult').