What are characteristic elements of a defense in military operations?

The characteristic elements of a defense in military operations include disruption, flexibility, mass, and concentration, making this choice correct.

Disruption refers to actions that impede or interrupt the enemy's plans, strategies, and movements. This is critical in defensive operations, as it can destabilize the enemy's offensive actions and create opportunities for counterattacks. Flexibility allows forces to adapt to changing battlefield conditions and threat levels, enabling defenders to respond effectively to enemy maneuvers and adjust their tactics as needed.

Mass involves the concentration of combat power at decisive points to maximize the defensive force's effectiveness. This is often achieved by positioning resources strategically, ensuring that when the enemy engages, there is enough strength to hold the line or repel their advances. Concentration emphasizes the need for defenders to focus their resources on specific areas where the enemy is most likely to strike or where the battle can be turned in their favor.

The other options include important elements in military operations but do not capture the essential characteristics specific to defense. For example, preparation, security, and communication are vital for any operation, but they do not specifically highlight the proactive elements needed in a defense. Similarly, speed, surprise, and sustainability are more associated with offensive operations rather than the primary focus of