The length of day and night varies during the year because the earth rotates on a 23.5 degree axis.
(The length of day and night; varies; T:during the year; because the earth rotates on a 23.5 degree axis) (the earth; rotates; L:on a 23.5 degree axis)
The length of day and night the earth
varies rotates
T:during the year because the earth rotates on a 23.5 degree axis
L:on a 23.5 degree axis