The are important to maintaining discipline in the army

Survivance, strategy and organization.

Explanation:

In the army it is extremely important to maintain discipline because army men are constantly exposed to life-threatening situations, therefore, errors can be crucial and define life or death of a person. Strategy is also part of the reason why in the army discipline is key, as battalions or groups of army men are meant to move as a unit in order to achieve the objectives of the strategy, if there's a person or a group that's not doing their part correctly the whole operation is at risk.