Because the earth's axis of rotation is tilted by 23.5 degrees from the normal to the plane of its path around the sun, the northern hemisphere is inclined toward the sun during its summer and away from the sun during its winter.
(the earth's axis of rotation; is tilted; by 23.5 degrees from the normal to the plane of its path around the sun) (the northern hemisphere; is; inclined toward the sun)
the earth's axis of rotation the northern hemisphere
is tilted is
by 23.5 degrees from the normal to the plane of its path around the sun
inclined toward the sun