Which layer is responsible for earth's magnetic field? Why?

Give a geographical reason for each of the following:

(i) Temperature starts rising gradually towards the interior of the earth.
(ii) The asthenosphere is in a semi-molten state.
(iii) The inner core of the earth is in a solid state.

Look at the figure on the side and answer the questions:

(i) Label the parts: (1), (2), (3), (4) and (5).
(ii) Name the state (solid, liquid or gas) in which each part exists.
(iii) Which part of the earth is suitable for human habitation? Why?

Give a geographical reason for each of the following:

(i) Nife is so called.

(ii) The core of the earth is the most inaccessible part of the earth.

(iii) The earth's crust undergoes many changes.