This is the 4855th most frequent Russian word.
интересуются
"Are interested (in)"
The word 'интересуются' is used to describe the subject's interest in something specific, which in this case is 'история' (history).
Они интересуются историей.
They are interested in history.
Here, 'интересуются' conveys the interest shown by a group ('студенты') in a broad topic ('культура разных стран').
Много студентов интересуются культурой разных стран.
Many students are interested in the culture of different countries.
In this sentence, 'интересуются' discusses the interest attribute of his friends ('его друзья') towards 'наука' (science).