What are the two sources of heat in the earth's interior?

A. leftover heat from formation and radioactive decay

B. magma and liquid outer core

C. radioactive decay and convection currents

D. sunlight and meteor impacts

The two sources of heat in the earth's interior are-

A. The leftover heat from formation and radioactive decay

Explanation:

The leftover heat from the time when the planet was formed, which has not yet been lost, is a source of internal heating of the earth. There are various radioactive elements present deep inside the earth and they are decaying slowly and gradually and emit heat into the earth's interior.