Fact 1: Plants detect and respond to the daily cycle of light and darkness.

Fact 2: All daily cycles of the celestial objects are caused by the rotation of the Earth.

Given the two facts above, answer the question "Plants detect and respond to" with the following options: 
- sub-units of species
 - ocean tides
 - volcanic activity
 - heat and light
 - plate shifts
 - microorganisms
 - the rotation of the Earth
 - Temperature changing


 

       the rotation of the Earth  