Final answer:
The statement is false. The hydrosphere refers to Earth's water, not its internal layers such as the core, mantle, and crust which are composed of rock and metal, with the outer core playing a role in generating Earth's magnetic field.
Step-by-step explanation:
The statement that the hydrosphere is the Earth's intensely hot core, thick mantle composed mostly of rock, and thin outer crust is false. The hydrosphere actually refers to all of the water on Earth's surface, including oceans, lakes, rivers, and groundwater. In contrast, the Earth's structure consists of the crust, mantle, and core. The crust is the outermost layer of the Earth, which is made of rock and varies in thickness. Beneath the crust is the mantle, a thick layer composed of more dense material that can flow slowly. The core, which is divided into a solid inner core and a liquid outer core, is primarily made of iron and nickel and is extremely hot. The outer core is responsible for the creation of Earth's magnetic field.