The physical cause of the precession is a torque (twisting) of the earth, caused mostly by the sun's and the moon's gravity pulling on the equatorial bulges of the earth.
(The physical cause of the precession; is; a torque (twisting) of the earth, caused mostly by the sun's and the moon's gravity) (a torque (twisting) of the earth; caused; mostly by) (the moon's gravity; pulling; on the equatorial bulges of the earth)
The physical cause of the precession a torque (twisting) of the earth the moon's gravity
is caused pulling
a torque (twisting) of the earth, caused mostly by the sun's and the moon's gravity
mostly by
on the equatorial bulges of the earth