The sun is the ultimate source of energy for life systems while heat convection currents deep within the Earth are an energy source for gradually shaping the Earth s surface.
(The sun; is; the ultimate source of energy for life systems) (heat convection currents deep within the Earth; are; an energy source for gradually shaping the Earth s surface)
The sun heat convection currents deep within the Earth
is are
the ultimate source of energy for life systems
an energy source for gradually shaping the Earth s surface