In one type of periodic change, the angle of tilt in the earth's axis varies over periods of about 41,000 years.
(the angle of tilt in the earth's axis; varies; T:over periods of about 41,000 years; L:In one type of periodic change)
the angle of tilt in the earth's axis
varies
T:over periods of about 41,000 years L:In one type of periodic change