Newton's Third Law:

* For every action, there is an equal and opposite reaction.

The Apple and the Earth:

* Apple's Action: The apple is attracted to the Earth by gravity.

* Earth's Reaction: The Earth is also attracted to the apple by gravity.

The Difference:

* Mass: The Earth is vastly more massive than the apple.

* Acceleration: While both objects experience the same force of gravity, the apple accelerates much more noticeably towards the Earth because it has much less mass. The Earth, in contrast, experiences a tiny acceleration towards the apple (so small that it's impossible to notice).

Think of it this way:

Imagine a tug-of-war between a small child and a very large adult. Both are pulling with the same force, but the child will move much more because they have less mass. The adult will move a tiny bit, but it's practically unnoticeable.

In Summary:

The apple and the Earth *both* fall towards each other due to gravity. However, the Earth's enormous mass means its acceleration is incredibly small compared to the apple's. This makes it seem like only the apple is falling.