GEOLOGY

Detailed explanation-1: -There are three chemical layers; the crust, the mantle and core and five recognised physical layers; the lithosphere, asthenosphere, mesosphere, outer core and inner core.

Detailed explanation-2: -Scientists can tell by observing the seismic waves that are recorded all over the surface of the earth from distant earthquakes. The seismic waves are reflected (bounced off) layers of different density, and they are refracted (bent) when they enter layers of different density.

Detailed explanation-3: -If we subdivide the Earth based on rheology, we see the lithosphere, asthenosphere, mesosphere, outer core, and inner core. However, if we differentiate the layers based on chemical variations, we lump the layers into crust, mantle, outer core, and inner core.

Detailed explanation-4: -Crust: the outer layer of rock on which humans and animals live and plants grow. Mantle: a semi-solid magma layer consisting of iron, magnesium, and silicon. Core: centrally located solid mass of metal (inner core) and a liquid mass of iron and nickel (outer core). 30-Oct-2021