Nuclear fusion generates the energy that is released by stars. In the great majority of stars, it's the fusion of hydrogen nuclei to form helium nuclei plus energy. In very old stars, the nuclei of heavier elements are fused, forming even heavier ones.
Upwelling is a process of the winds that drives away the warm water from the surface and bring up the cold and dense water from below.
Obliquity is the nature of the axial tilt of the earth i.e 23.5 ° Due to the equator bulge and other properties of the earth.
The thermohaline circulation is the global circulation of the waster that is created by the gradient flow of the surface heat and the freshwater influxes.
Milankovitch cycles are the effect of the changes in the earth's movements in climatic patterns over a thousands of years period.
Eccentricity is the orbital rotation of the earth around the sun on its axis and has more of a circular elliptical path.
The precession is the change in the orientation of the axial tilt of the planet in reference to the rotating body.
