Remember, it is the spinning of the Earth that causes the observed motions of the Sun and the stars over the course of the day (or night) - but there are two different time spans here - which one corresponds to the rotation period of the Earth.
(it; is; the spinning of the Earth) (the spinning of the Earth; causes; the observed motions of the Sun and the stars over the course of the day (or night) (two different time spans here; corresponds; to the rotation period of the Earth)
it the spinning of the Earth two different time spans here
is causes corresponds
the spinning of the Earth
the observed motions of the Sun and the stars over the course of the day (or night
to the rotation period of the Earth