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.
The promotion point cutoff scores are typically higher for the Secondary Zone as well. Army Promotion Criteria â Promotions to Sergeant (E-5) 1  Primary Zone: 8 months TIG as an E-4 and 36 months (3 years) TIS.  Secondary Zone: 4 months TIG and 18 months TIS.