You are presented with the question "what causes day and night cycles on a planet?" and the following answer choices: 
- seasons
 - carbon dioxide
 - flow of electrons
 - gravitational pull
 - fissures of hot, acidic water
 - spinning on its axis
 - heat energy
 - energy of moving objects

Now knowing that aplanet rotating causes cycles of day and night on that planet and rotation simply means how long it takes a planet to spin on its axis, choose the best answer.


 

      spinning on its axis   