That is, the glacial/ interglacial cycles are believed to be associated with changes in the precession of the Earth's axis (~23,000 year period), variation in the Earth's axial tilt (~41,100 year period), and changes in the eccentricity of the Earth's orbit around the sun (~ 100,000 year period).
(the glacial/ interglacial cycles; are believed; ) (the glacial/ interglacial cycles; to be associated; with changes in the precession of the Earth's axis)
the glacial/ interglacial cycles the glacial/ interglacial cycles
are believed to be associated
with changes in the precession of the Earth's axis