What effect does gravity have on the horizontal component of a projectile's motion?

Gravity acts vertically on a projectile, influencing its vertical motion, but it does not exert a force in the horizontal direction. As a result, the horizontal component of a projectile's motion remains constant in the absence of air resistance. The speed of the projectile in the horizontal direction does not change because there are no horizontal forces acting on it after the launch. Therefore, gravity has no effect on the horizontal component, allowing the projectile to maintain a constant horizontal velocity throughout its flight.