Summarize the processes by which planetary interiors get hot. ( answer in your own words and give the reference, )

Process of volcanism, erosion and tectonics.

Explanation:

Earth is divided into two-sphere as the land sphere and water sphere in which the water sphere has 70% of the earth volume and 30% of the land surface here in the interior of the earth there are certain forces i.e tectonic in nature act upon the landmass by the impact of erosion and deposition. Volcanism is considered as the dominant process of upwelling of hot lava and magma at the surface of the earth through ether fissure eruption, or vent explosions. Other processes like the heating of lands are much more pronounced in the northern hemisphere due to the solar radiation and heat from above. Interiors of the planet are considered as hot and humid as they directly observe the incoming light from above and their rate of spreading this heat is low and slow. Salinity,  higher density and older age of rocks are found near the interiors of the planet as compared to when we move away from the interior to the coasts and oceans which are much open and separate.