If gravity did NOT affect the path of a horizontally thrown ball, the ball would continue to move in a straight line at a constant speed.

Here's why:

* Newton's First Law of Motion: An object at rest stays at rest, and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

* Gravity: In our world, gravity is the unbalanced force that acts on the ball, pulling it downwards and causing it to follow a curved path.

Without gravity, the ball would just keep going in the direction it was initially thrown, forever.