Answer:
plants provide shelter and air for the animals
and when animals die they decompose and become fertilizer for the plant 
 
        
             
        
        
        
Answer:
This happens when the air has a lot of moisture and when the temperature is low (because in this way the water in the air condenses). So if a weather station predicts that warm humid air will pass over much cooler land, the precaution must be to use healights and drive slowly because it will probably be dense fog.
 
        
             
        
        
        
Answer:
Steroids are also lipids but they have a carbon skeleton of four connected rings (no glycerol here) (3.9, pg 41). The different properties of different steroids are due to the attached functional groups. Cholesterol is a steroid that can be modified to form many hormones.
Explanation:
 
        
             
        
        
        
I think its C. 
I hope this helps and please do correct me if im wrong.
        
                    
             
        
        
        
Using energy is the answer to this question :)