Question

there are discontinoities in the interior of the earth

Answer 1

The inside structure of earth is split into spherical shells such as outer silicate solid crust, a highly viscous asthenosphere & mantle, an outer course which is much lesser viscous compared with mantle as well as a solid inner core.

The scientific understanding of earth internal structure is based upon the observations of bathymetry and topography, observations of rock in outcrop and analysis of seismic waves.