Which factor can significantly influence bullet trajectory?

The correct answer is that all of the options presented can significantly influence bullet trajectory.

Wind speed affects the trajectory by applying lateral forces on the bullet as it travels through the air. Higher wind speeds can cause the bullet to drift off course, which is crucial to account for when making long-range shots.

Humidity plays a significant role as well since it can affect the air density. Lower humidity generally means denser air, which can provide more drag on the bullet and impact its distance and drop.

Temperature also influences bullet trajectory because warmer air is less dense than cooler air. In colder conditions, the increased air density can result in greater drag, which can affect both the distance a bullet travels and its overall performance.

Understanding that all these environmental factors interplay with one another allows shooters to make more accurate calculations for adjustments in aiming and compensatory measures required for optimal performance.