<span>Atherosclerosis is a common cause, because there is a lack of blood flow in the person's body, and this can cause a male to be impotent. 
Diabetes is also a common cause because once again it causes less blood flow. 
In a younger man, a cause could be anxiety. This is because nervousness and being anxious can lessen blood flow.
If you have choices, I suggest choosing one that has to do with less blood flow happening, which that is the main cause.
I hope that this could possibly help you with your studies, and have an amazing day. If you have any more questions, send me a pm. </span>
        
             
        
        
        
Correct answer: B). The phagocytotic barrier, which is a part of innate immunity
The scenario represents the phagocytosis, which is a type of endocytosis by which the cell engulfs microbial pathogens. The main cells of the immune system that are involved in phagocytosis include macrophages, neutrophils, and dendric cells. 
It is a mechanism which is used by the immune system to kill and processing of antigen that play an important role in innate immune response. 
Hence, the correct answer would be option B.
 
        
                    
             
        
        
        
The first step in protein synthesis is the transcription of mRNA from a DNA gene in the nucleus. At some other prior time, the various other types of RNA have been synthesized using the appropriate DNA. The RNAs migrate from the nucleus into the cytoplasm.