During the first 800 years, the graph shows a gradual decrease, which is thought to have been caused by the way the tilt in the Earth's axis changes in relation to the Sun and the Earth's orbit around the Sun.
(the graph; shows; a gradual decrease, which is thought to have been caused by the way the tilt in the Earth's axis changes in relation to the Sun and the Earth's orbit around the Sun; T:During the first 800 years) (a gradual decrease; is thought; to have been caused by the way the tilt in the Earth's axis changes in relation to the Sun and the Earth's orbit around the Sun) (a gradual decrease; to have been caused; by the way; the tilt in the Earth's axis changes in relation to the Sun and the Earth's orbit around the Sun)
the graph a gradual decrease a gradual decrease
shows is thought to have been caused
a gradual decrease, which is thought to have been caused by the way the tilt in the Earth's axis changes in relation to the Sun and the Earth's orbit around the Sun T:During the first 800 years
to have been caused by the way the tilt in the Earth's axis changes in relation to the Sun and the Earth's orbit around the Sun
by the way the tilt in the Earth's axis changes in relation to the Sun and the Earth's orbit around the Sun