Answer:
Angiotensin II atrial natriuretic peptide(ANP) lowers blood pressure.
Explanation:
Increase in plasma volume leads to increase in blood pressure and a decrease in plasma level also leads to a decrease in the blood pressure. ANP is an enzyme which stimulates the decrease in blood levels through certain factors thereby causing a decrease in the blood pressure.
Meanwhile ADH stimulates increase in blood plasma levels thereby increasing the blood pressure.
 
        
                    
             
        
        
        
Answer:
It's C. They are mostly made up of hydrogen and helium 
 
        
             
        
        
        
<h2>Tropomyosin</h2>
Explanation:
This protein is most likely:  Tropomyosin.
Sacromere is the structural unit of myofibrils i.e. the fibres of the muscles. 
Tropomyosin is the muscle protein that function in contraction of muscle filaments.They are arranged laterally along the myofilament. When the researcher is observing the sacromere, she is observing the muscle fibre.  So, the protein that lines the periphery along the thin filament is more likely to be tropomysin.