You are presented with the question "What are two things that are important for plants?" and the following answer choices: 
- organic material
 - Bubbles and soap
 - Humidity and protection
 - excretory structures
 - Sand and rocks
 - Darkness and cool winds
 - food and shelter
 - genetic diversity

Now knowing that agreenhouse is used to protect plants from the cold and the air in the greenhouse is humid, choose the best answer.


 

   Humidity and protection      