Regarding the earth's composition it would not be true to say which of the following I. The crust is composed of different types of rocks. II. The central nucleus is fluid. III. Below the crust the material is totally solid.

Statement III is false because the mantle, which lies below the crust, is composed of solid rock that behaves plastically over geological time, not totally solid in the sense of being rigid throughout, but certainly not liquid. Statement II is also technically debated as the outer core is liquid, but III is the most clearly incorrect statement in standard geological contexts.