All members of congress serve on at least one ……

1. department
2. committee
3. division
4. organization
5. branch

All members of congress serve on at least one division (C)

i.e. the Senate and the House of Representatives.

Explanation:

"Congress" is a "bicameral legislature" that is often used as a descriptive term for the collective body of legislatures. It is under Article 1 of the Constitution where the United States Congress was created. There is a clear division of the two houses. One is called the Senate and the other is called the House of Representatives. The members of senate are called senators and the members of the House of Representatives are referred as congressmen or congresswomen. Each of these members are elected by direct popular vote.