The President's Cabinet

Clearly one of the most popular homework assignments in America -- "Name the president's Cabinet."

The Cabinet-level departments are listed here in order of presidential succession.

Secretary of State: Mike Pompeo
Brief Summary of Department's Role
Web Address: http://www.state.gov/

Secretary of the Treasury: Steven Mnuchin
Web Address: http://www.ustreas.gov/

Secretary of Defense James N. Mattis (Until Jan. 31, 2019.)
Deputy Secretary of Defense Patrick M. Shanahan (Effective Feb. 1, 2019.)
Web Address: http://www.defenselink.mil/

Acting Attorney General Matthew G. Whitaker
Web Address: http://www.usdoj.gov/

Secretary of the Interior: Ryan Zinke (resigning effective Jan. 1, 2019)
Web Address: http://www.doi.gov/

Secretary of Agriculture: Sonny Perdue III
Web Address: http://www.usda.gov/

Secretary of Commerce: Wilbur L. Ross, Jr.
Web Address: http://www.commerce.gov/

Secretary of Labor: R. Alexander Acosta
Brief Summary of Department's Role
Web Address: http://www.dol.gov/

Secretary of Health and Human Services: Alex Azar
Web Address: http://www.hhs.gov/

Secretary of Housing and Urban Development:Ben Carson
Web Address: http://www.hud.gov/

Secretary of Transportation: Elaine Chao 
Web Address: http://www.dot.gov/

Secretary of Energy: Rick Perry
Web Address: http://www.doe.gov/

Secretary of Education: Betsy DeVos
Web Address: http://www.ed.gov/

Acting VA Secretary Robert Wilkie
Web Address: http://www.va.gov/

Secretary of Homeland Security Kirstjen M. Nielsen
Web Address: http://www.dhs.gov/

Note: While not officially part of the Cabinet, the following positions currently have Cabinet-rank status:
White House Chief of Staff
Administrator of the Environmental Protection Agency
Director of the Office of Management & Budget
United States Trade Representative
United States Ambassador to the United Nations
Chairman of the Council of Economic Advisers
Administrator of the Small Business Administration

Why is it called "cabinet?" When did it first meet? How much do the secretaries make, who picks them and how long do they serve?