Какой падеж у слова "тренера" в словосочетании "профессия тренера"

Exercise E. Ответьте на вопросы:

1.                What is the political system of the USA?

2.                Who is the Head of the state?

3.                What branch does the Congress represent?

4.                What does the Congress do?

5.                How many senators are there?

6.                Who can veto a bill in America?

7.                What is the executive power in America?

8.                What does the executive branch consist of?

9.                What is the third branch of the American government?

10.Who is the President now? What party does he represent