Hamilton
Yes, she is; she heads the state department.
One of the principal purposes of the Cabinet (drawn from Article II, Section 2 of the Constitution) is to advise the President on any subject he/she may require relating to the duties of their respective offices.
The Secretary of Commerce, a member of the President's cabinet.
Most of them hold the title of Secretary of whatever department they head, Secretary of State being an example. The Attorney General heads the justice department. In years past, the Postmaster General was a cabinet member. The usual form of address is "Mr. (or Madame) Secretary", if that's what you were asking.
Secretary of the Department of Homeland Security
The cabinet members each run one of the major departments of the US government. The employees of these departments are under the direction of the cabinet member who heads their department.
None specifically, but Article two Section two of the Constitution mentions that any cabinet member is allowed to be hired by the permission of Congress.
In the United States Federal Government, the department responsible for dealing with financial matters is the Department of the Treasury, headed by the Secretary of the Treasury, a member of the president's cabinet.
there are no requirements to be a cabinet member. they are chosen at the whim of a president
The cabinet member that is in charge of foreign affairs is the Secretary of State. The Secretary of State is John Kerry who is a former Senator of Massachusetts.
The Secretary of Defense is in charge of active duty armed forces. Activities regarding former service members are overseen by the Department of Veterans Affairs.