Final answer:
Functional area analysis is the key element in identifying the best Course of Action (COA) for a mission by evaluating supportability from different functional perspectives within a collaborative environment.
Step-by-step explanation:
The phrase missing in the provided statement is 'functional area analysis.' The functional area analysis helps to identify the Course of Action (COA) that best accomplishes the mission by determining the supportability of each COA from individual functional perspectives and collaborating in a knowledge-based environment.
The functional area analysis involves a systematic examination of the components and resources required for a given operation or plan. This analysis ensures that all functional areas, such as logistics, communications, and intelligence, among others, are considered. By assessing each COA from the various functional perspectives, stakeholders can collaborate effectively to select the most viable option that maximizes efficiency and effectiveness while minimizing risk.