- Gravity causes objects that have mass / substances to be pulled down / to fall on a planet
- Gravity is a kind of force
- A ball is a kind of object
- Therefore, gravity is the force that pulls the ball towards the planet

Hence, gravity is the force that pulls the ball towards the planet
Question
A student drops a ball. Which force causes the ball to fall to the ground?

Context
- Gravity causes objects that have mass / substances to be pulled down / to fall on a planet 
- Gravity is a kind of force 
- A ball is a kind of object