Answer:
I don't understand thequestion
 
        
             
        
        
        
All viruses have is a protein coat and a core of genetic material, either RNA or DNA. Unlike bacteria, viruses can't survive without a host. They can only reproduce by attaching themselves to cells. Unlike bacteria, most viruses do cause disease, and they're quite specific about the cells they attack.
        
             
        
        
        
Birds because they spread seeds
        
             
        
        
        
It is killing of population forcing us to self quarantine and stay away from people. Quarantine is marking many people depressed because we can’t talk or visit people face to face and it’s harming many people with anxiety and depression it’s making them worse.
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<u>Answer:</u>
<em>There are innermost serious membranes that cover the heart is Parietal Pericardium.</em>
<u>Explanation:</u>
Heart is <em>covered by pericardium</em> in two sides, inner and outer sides. The inner membrane is parietal pericardium and the outer one is visceral pericardium. Pericardium is made up of <em>fiber tissues</em> that strongly protect the heart from all around. 
The<em> main function of pericardium</em> is to protect the heart from any injuries and prevent the infections. The serious pericardium helps in<em> lubricating the heart. </em>