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