Answer:
I am not really sure, but I think Fr.
Explanation:
 
        
                    
             
        
        
        
The more acidic the substance is, the more the iron nails will corrode (this obviously depends on what your experiment is but hope this helped in some way)
        
             
        
        
        
Answer:
1.8g
Explanation:
Initial volume = 43.5ml
Final volume = 49.4ml
Mass = 10.88g
Density = ?
Volume = Final volume - initial volume
 = 49.4 - 43.5
 = 5.9ml
Density = Mass/volume
Density = 10.88/5.9
 = 1.8g/ml
 
        
             
        
        
        
Answer:
C. the use of hydrogen gas as an electron donor.
Explanation:
Hydrogenotrophy is the convertion of hydrogen gas to other compounds as part of its metabolism.