Heat travels in slow convection currents of solid materials within Earth's mantle. Heat that rises in these currents

Question

A.
is provided externally by the Sun.
B.
is provided externally by gravitational energy in the Solar System.
C.
is a by-product from the decay of Earth's radioactive isotopes.
D.
is a by-product of frictional forces between Earth's tectonic plates as they slide past one another.

Answer 1

Heat that rises in convection currents within Earth's mantle is primarily:

C. is a by-product from the decay of Earth's radioactive isotopes.

This heat originates from the radioactive decay of isotopes such as uranium, thorium, and potassium found within the Earth, contributing to the thermal energy that drives mantle convection.