Answer:
Rough endoplasmic reticulum differ from smooth endoplasmic reticulum by the presence and absence of ribosomes in their surface.
Explanation:
Rough endoplasmic is named so because RER contain ribosomes at their surface and due to the presence of ribosomes rough endoplasmic reticulum play an importnt role in protein synthesis or translation.
  Whereas smooth endoplasmic reticulum does not contain any ribosome in its surface.smooth endoplasmic reticulum helps in the biosynthesis of lipid and steroids along with detoxification of toxic compounds.
 
        
             
        
        
        
You didn't put any answer choices, but air and water are generally the greatest.
        
                    
             
        
        
        
1) Pneumothorax in this case; a spontaneous pneumothorax can be life threatening cause the lung will eventually cause vacuum used by the lung to fill with air, and as you constantly expand your lung it decreases and collapses. So C is going to be the answer.
2) Acetylcholine is the hormone responsible for the "Rest and digest". It is the direct opposite of the Fight and Flight reaction which is marked in Bronchodilation, Increased HR, and increased BP. B
3) Secretin is responsible for stimulating the release of bile by the liver. Secretin is released by the duodenum, the junction of the stomach and small intestines. B
        
             
        
        
        
Answer:
I think the answer is 2 or 1 
Explanation:
(so sorry if im wrong)
 
        
             
        
        
        
Answer:
b. hibernation to lower metabolism in the winter
Explanation:
Tundra, besides the one I live in apparently, are very, very dry because of the cold. This means that it may be helpful to hibernate for the part of the year where it is even too cold for plants and other animals.