They breathe through their skin. Air dissolves on the mucus of their skin, so they MUST stay moist to breathe. 
If worms dry out, they suffocate. As fresh air is taken in through the skin, oxygen is drawn into the worm's circulatory system, and the worm's hearts pump the oxygenated blood to the head area.
 
        
             
        
        
        
Enzymes speed up a biological reactions by lowering the activation energy. 
Hope it helped you, and have a great day!
-Charlie 
Thank you so much!!!!!!!!
        
                    
             
        
        
        
Answer: Option D 
Explanation:
The practice which has been prevailing from a long time is considered as culture.Farming is also a type of culture which is being practiced from a longer period of time in the society.
The farming is also a type of culture which was invented somewhere and started spreading from there to other places.
This practice helped mankind  in providing food and resources to the people of nation.
 
        
             
        
        
        
Answer:
This is just the order of taxonomic groupings. 
Domain (Broadest)
Kingdom
Phylum 
Class 
Order 
Family 
Genus 
Species (Most specific)