Which factor does NOT affect the trajectory of a round fired from artillery?

The trajectory of a round fired from artillery is influenced by several physical factors that affect how the round travels through the air and interacts with the environment. The type of ammunition, wind speed, and humidity all have significant impacts on the trajectory.

Type of ammunition can affect the weight, shape, and ballistic properties of the projectile, which directly influences how it behaves when fired, including factors like range and accuracy.

Wind speed can alter the path of the projectile as it flies, causing drift due to lateral forces acting on it, which can lead to a miss if not accounted for.

Humidity impacts the density of the air; higher humidity can reduce air density, affecting drag on the projectile and thus altering its behavior during flight.

The color of the projectile, however, does not influence its physical properties or interaction with the environment in any meaningful way regarding trajectory. While color might have aesthetic or observational significance, it does not play a role in the physics of how the round travels through the air. Therefore, this factor does not affect the trajectory, making it the correct answer.