GEOLOGY

Detailed explanation-1: -The Earth gets hotter as one travels towards the core, known as the geothermal gradient. The geothermal gradient is the amount that the Earth’s temperature increases with depth.

Detailed explanation-2: -(i) The increasing depth causes the earth density to increase. The earth becomes heavier. When the earth becomes heavier, the earth would be much hotter, increasing volcanic activity etc. The earth might not be a suitable place to live.

Detailed explanation-3: -’ In contrast, the Earth gets hotter and hotter at depth primarily because the energy of radioactive decay is leaking outwards from the core of the planet. While this geothermal energy is transferred to ocean water along the seafloor, the effect is so small that it’s immeasurable by direct means.