Here's why:

* The Skin (Crust): The apple's thin skin is similar to Earth's crust, the outermost layer, which is relatively thin compared to the rest of the planet.

* The Flesh (Mantle): The fleshy part of the apple, just beneath the skin, can be compared to Earth's mantle, the thickest layer. It's mostly solid but can behave like a very viscous fluid over long periods.

* The Core (Core): The apple's core, containing seeds, is analogous to Earth's core, which is made up of a solid inner core and a liquid outer core.

While not a perfect analogy, the apple helps visualize the relative sizes and properties of Earth's layers.