Once you have enabled AI Servo mode and selected the correct focus points (if you want to adjust them from how the camera is currently set up), the only control you need is the shutter button -- just pressing this halfway will enable focus tracking on the focus points that are enabled.
The Social Security Act was enacted August 14, 1935. The Act was drafted during President Franklin D. Roosevelt's first term by the President's Committee on Economic Security, under Frances Perkins, and passed by Congress as part of the New Deal.
Enacted in 1935, FICA provides for Social Security under Title II of the act. The ability to tax income to fund Social Security is provided in Title VIII. According to the Social Security Administration, the provisions for collecting FICA taxes were given under the Internal Revenue Code by amendments adopted in 1939.