The large object that has a crust, core, and mantle is a planet.

This structure is true for most rocky planets in our solar system, including Earth.

Here's a breakdown:

* Crust: The outermost layer, relatively thin and composed of various types of rock.

* Mantle: The thickest layer, mostly solid rock, but can behave like a very viscous fluid over long periods.

* Core: The innermost layer, composed mainly of iron and nickel. The inner core is solid due to immense pressure, while the outer core is liquid.