You are presented with the question "Sleeping at night and working during the day is determined by what thing happening?" and the following answer choices: 
- clouds forming
 - planet rotating
 - heat energy
 - dehydration
 - solar flares
 - animal reproduction
 - Animal survival
 - sweating

Now knowing that aplanet rotating causes cycles of day and night on that planet and our bodies and senses adjust to the cycle of day and night so that we may work in the day and sleep at night, choose the best answer.


 

  planet rotating       