The seasons on earth are created by the
a. tilt of earth on its axis, and the revolution of earth around the sun.
b. gravitational pull of the galaxy and dwarf planets.
c. location of earth's hemispheres, separated by the equator.
d. location of earth's moon and its gravitational pull.

The seasons on Earth are created by the tilt of Earth on its axis, and the revolution of Earth around the sun. The planet Earth has a tilt of 23.5 degrees relative to the "ecliptic plane" (which is the imaginary surface made around the path around the sun) 

The best answer is (a) which is universal law is in effect at all times. it is constantly at play in everything we do and governs our lives. it is also important to note that universal law applies to not only everything on earth, but everything in the universe as well, which is another reason why it is in effect at all times.