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

Fact 2: All plants are of bush type.

Given the two facts above, answer the question "what detects and responds to the daily cycle of light and darkness?" with the following options: 
- fens
 - apples
 - oxygen
 - Oak
 - gravity
 - amoeba
 - earth's rotation
 - bushes


 

        bushes 