Правильно ли написаны вопросы? 1)What does the term “сollege” mean? 2)What is a liberal art institutions? 3)what is community

1) What does the term “сollege” mean? - correct;

2) What are liberal art institutions? - without \"a\", as the Noun is in plural (\"institutions\");

3) What is a community college? - with \"a\", as the Noun is in singular (\"college\");

4) What is the academic calendar for a university in the US? - with \"a\", as the Noun is in singular (\"university\") and has the meaning \"any\";

5) Why is it not so easy to stay in university? - introductory \"it is\" in the converted form (as it\'s a question) is omitted.