Neurotransmitters are chemical messengers that coordinate the transmission of signals from one nerve cell (neuron) to the next.eurotransmitters are chemical messengers that coordinate the transmission of signals from one nerve cell (neuron) to the next.
Soldiers in the secondary zone may be boarded with 16 months time-in-service and four months time-in-grade as of the first day of the board month. The time-in-service requirement for attaining eligibility for promotion to SSG is 84 months Active Federal Service for the primary zone and 48 months for the secondary zone.
Primary Zone/Secondary Zone. There are two promotion processes known as âPrimary Zoneâ and âSecondary Zone.â Most enlisted soldiers are promoted in the âPrimary Zone.â The âSecondary Zoneâ is for soldiers considered to be âexceptional performersâ and gives them an early shot at promotion.