Which characteristic of fire refers to the shape of the projectile's path?

The correct answer is found in the concept of trajectory, which specifically refers to the path that a projectile follows when it is fired. This concept is crucial in understanding how various factors, such as angle of fire, force of the projectile, and external conditions like wind, affect the movement of the projectile through the air.

In military applications, knowing the trajectory allows for better target acquisition and engagement strategies. A proper understanding of trajectory is essential for effective range estimation and can significantly impact the effectiveness of the fire support provided in combat scenarios.

The other options relate to different aspects of how projectiles operate or interact with the environment. Maximum ordinance refers to the maximum height attained by a projectile. Beaten zone describes the area where rounds hit the ground after being fired, while danger space is the area in which a projectile can be effective in incapacitating a target without risking safety to friendly forces. Each of these terms has its specific context, but none encapsulate the idea of the projectile's trajectory as the correct answer does.